OTTAWA - The Foreign Affairs Department has called in Algeria's ambassador to Canada to get more information on why the country's prime minister labelled some of the hostage-takers in last week's gas-plant siege as Canadian.

The diplomatic discussion was part of Ottawa's ongoing efforts to either confirm or debunk reports that there were two Canadians among the terrorists involved in the attack on the remote plant in the Algerian desert.

The federal government is trying to determine whether any key papers that might point to Canadian involvement are valid or fake, and they're growing frustrated with the lack of detailed information coming from Algerian officials.

Canadian diplomats in Algeria are also requesting access to the information the Algerians are using to identify any of the militants as "Canadian," a government official said.

Some 37 hostages and 29 militants were killed when Algerian forces stormed the complex; five other foreign workers remain unaccounted for.

Meanwhile, U.S. observers played down any concerns Tuesday that the reports could undermine confidence in Canada south of the border.

Even if Canadians are indeed found to be among the militants in Algeria, it's not likely to cause any lingering security concerns south of the border, say U.S. observers.

That's because the two North American neighbours — the world's two largest trading partners — are already seeing the benefits of more than 10 years of efforts to deepen co-operation on security and trade.

The perimeter security pact, signed by U.S. President Barack Obama and Prime Minister Stephen Harper some 13 months ago, has deepened intelligence sharing and debunked U.S. perceptions that Canada was a haven for terrorists.

Debunking that view became a major preoccupation for Canadian diplomats following the Sept. 11, 2001, attacks on the U.S., when erroneous reports initially emerged that some of the 9-11 hijackers had gained entry through Canada.

"I don't think it will be a rift, but it's a reminder certainly for the Obama administration that some of these problems have an impact close to home," said Chris Sands, a veteran expert on Canada-U.S. relations with Washington's Hudson Institute.

More problematic, though, was the 1999 arrest of Algerian-born, Montreal-based al-Qaida member Ahmed Ressam, who was caught trying to enter the U.S. in a plot to blow up Los Angeles International Airport on New Year's Eve.

"In some ways, the United States was always a little more worried about the Algerian community that settled in Montreal and what they were up to," said Sands.

"After Ressam, the Americans were saying this community is a problem … and Canada was in some sort of denial, saying these are legitimate Canadians, we can't single them out, this is unfair, we're casting aspersions."

Over the last 10 years, "Canada started to take the challenge more seriously as well — not accusing the whole community of being a problem, but trying to do a better job of gathering intelligence."

Even if Canadian documents were used by terrorists in North Africa, it won't be enough to undermine confidence among U.S. government officials, added David Biette, director of the Canada Institute at Woodrow Wilson International Centre in Washington.

"If we looked at any bad thing that someone carrying a Canadian passport did anywhere in the world, to have it affect bilateral relations, I think we'd be wasting our time," said Biette.

"The security services that protect North America are good. They watch people going into Canada, they watch people going into the United States, and the effort is to keep the bad guys out and let the commerce go through."

The perimeter security deal, which will be phased in over several years, aims to smooth the passage of goods and people across the 49th parallel while bolstering defences along the continental border.

Citizenship and Immigration is the lead department on 10 perimeter initiatives. The most controversial may be a plan to keep track of everyone entering and leaving the country, with the help of information from the U.S.

Ottawa will help Washington do the same thing by systematically providing information on all travellers entering Canada from the U.S.

The plans entail greater exchange of both simple biographic and biometric data, and will be covered by a forthcoming Immigration Information Sharing Treaty.

That deeper co-operation, said Biette, is helping lay to rest any past concerns in the U.S. about Canada.

"Some of that means we're going to have to share information with each other," he said. "I am very aware and I think most Americans working on this are sensitive to the issue of privacy in Canada, which is different from Europe, different from the Americans."

The Canadian Press also obtained documents last month that showed Canada and the U.S. plan to join forces in order to better deal with "irregular flows'' of refugees that turn up in North America or migrate within the continent.

Note to readers: This is a corrected story. An earlier version referred to the Algerian president.

Earlier on HuffPost:

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  • An unidentified rescued hostage speaks to the media in a hospital Ain Amenas, Algeria, in this image taken from television Friday Jan. 18, 2013. Algeria’s state news service says nearly 100 out of 132 foreign hostages have been freed from a gas plant where Islamist militants had held them captive for three days. The APS news agency report was an unexpected indication of both more hostages than had previously been reported and a potentially breakthrough development in what has been a bloody siege. (AP Photo/Canal Algerie via Assiaciated Press TV) ** TV OUT ALGERIA OUT **

  • Unidentified rescued hostages pose for the media in Ain Amenas, Algeria, in this image taken from television Friday Jan. 18, 2013. Algeria’s state news service says nearly 100 out of 132 foreign hostages have been freed from a gas plant where Islamist militants had held them captive for three days. The APS news agency report was an unexpected indication of both more hostages than had previously been reported and a potentially breakthrough development in what has been a bloody siege. (AP Photo/Canal Algerie via Associated Press TV) ** TV OUT ALGERIA OUT **

  • Algerian special police unit officers secure the hospital in Ain Amenas, Algeria, Friday, Jan. 18, 2013, two days after the start of the terrorist attack at a gas plant. The hostage crisis in the remote desert of Algeria is not over, Britain said Friday, after an Algerian raid on the gas plant to wipe out Islamist militants and free their captives from at least 10 countries unleashed bloody chaos. (AP Photo/Anis Belghoul)

  • An unidentified rescued hostage receives treatment in a hospital in Ain Amenas, Algeria, in this image taken from television Friday Jan. 18, 2013. Algeria’s state news service says nearly 100 out of 132 foreign hostages have been freed from a gas plant where Islamist militants had held them captive for three days. The APS news agency report was an unexpected indication of both more hostages than had previously been reported and a potentially breakthrough development in what has been a bloody siege. (AP Photo/Canal Algerie via Associated Press TV) ** TV OUT ALGERIA OUT **

  • An unidentified rescued hostage speaks to the media in a hospital in Ain Amenas, Algeria, in this image taken from television Friday Jan. 18, 2013. Algeria’s state news service says nearly 100 out of 132 foreign hostages have been freed from a gas plant where Islamist militants had held them captive for three days. The APS news agency report was an unexpected indication of both more hostages than had previously been reported and a potentially breakthrough development in what has been a bloody siege. (AP Photo/Canal Algerie via Associated Press TV) ** TV OUT ALGERIA OUT **

  • This image from video provided by the SITE Intel Group made available Thursday Jan. 17, 2013, purports to show militant militia leader Moktar Belmoktar. Algerian officials scrambled Thursday Jan. 17, 2013 for a way to end an armed standoff deep in the Sahara desert with Islamic militants who have taken dozens of foreigners hostage, turning to tribal Algerian Tuareg leaders for talks and contemplating an international force. The group claiming responsibility — called Katibat Moulathamine or the Masked Brigade — says it has captured 41 foreigners, including seven Americans, in the surprise attack Wednesday on the Ain Amenas gas plant. Algerian Interior Minister Daho Ould Kabila said the roughly 20 well armed gunmen were from Algeria itself, operating under orders from Moktar Belmoktar, al-Qaida's strongman in the Sahara. (AP Photo/SITE Intel Group) THE ASSOCIATED PRESS HAS NO WAY OF INDEPENDENTLY VERIFYING THE CONTENT, LOCATION OR DATE OF THIS PICTURE. MANDATORY CREDIT: SITE Intel Group

  • This April 19, 2005 photo released by Statoil via NTB scanpix, shows the Ain Amenas gas field in Algeria, where Islamist militants raided and took hostages Wednesday Jan. 16, 2013. As Algerian army helicopters clattered overhead deep in the Sahara desert, Islamist militants hunkered down for the night in the natural gas complex they had assaulted Wednesday morning, killing two people and taking dozens of foreigners hostage in what could be the first spillover from France's intervention in Mali. (AP Photo/Kjetil Alsvik, Statoil via NTB scanpix) NORWAY OUT

  • This April 19, 2005 photo released by Statoil via NTB scanpix, shows the Ain Amenas gas field in Algeria, where Islamist militants raided and took hostages Wednesday Jan. 16, 2013. As Algerian army helicopters clattered overhead deep in the Sahara desert, Islamist militants hunkered down for the night in the natural gas complex they had assaulted Wednesday morning, killing two people and taking dozens of foreigners hostage in what could be the first spillover from France's intervention in Mali. (AP Photo/Kjetil Alsvik, Statoil via NTB scanpix) NORWAY OUT

  • JGC Corporation, or Nikki Manager of public relations Takeshi Endo, foreground, answers reporters' questions following Wednesday's attack at a natural gas complex in Algeria which involves the company's workers, at its headquarters in Yokohama, near Tokyo Thursday, Jan. 17, 2013. A militant group that claimed responsibility said 41 foreigners were being held after the assault on one of oil-rich Algeria's energy facilities. Two foreigners were killed. (AP Photo/Kyodo News) JAPAN OUT, MANDATORY CREDIT, NO LICENSING IN CHINA, HONG KONG, JAPAN, SOUTH KOREA AND FRANCE

  • Helge Lund

    Statoil Chief Executive Helge Lund answers questions about the situation in the gas field, jointly operated by BP, the Norwegian energy company Statoil and the Algerian state oil company Sonatrachfield along with Japanese company JGC Corp., in Ain Amenas in Algeria during a press briefing in Stavanger, Norway, Thursday, Jan. 17, 2013. In a desert standoff deep in the Sahara, the Algerian army ringed the natural gas complex where Islamist militants hunkered down with dozens of hostages Wednesday night after a rare attack that appeared to be the first violent shock wave from the French intervention in Mali. (AP Photo/NTB Scanpix, Kent Skibstad) NORWAY OUT

  • Helge Lund

    Statoil Chief Executive Helge Lund answers questions about the situation in the gas field, jointly operated by BP, the Norwegian energy company Statoil and the Algerian state oil company Sonatrachfield along with Japanese company JGC Corp., in Ain Amenas in Algeria during a press briefing in Stavanger, Norway, Thursday, Jan. 17, 2013. In a desert standoff deep in the Sahara, the Algerian army ringed the natural gas complex where Islamist militants hunkered down with dozens of hostages Wednesday night after a rare attack that appeared to be the first violent shock wave from the French intervention in Mali. (AP Photo/NTB Scanpix, Kent Skibstad) NORWAY OUT

  • STATOIL

    Statoil spokesman Ole Anders Skauby, centre right, talks to TV reporters outside Scandic Bergen Airport hotel where a drop-in center is established for relatives of hostages involved in the situation in Algeria. Militants are holding a number of foreigners hostages in the Sahara desert in revenge for Algeria's support of French efforts to remove Islamists from control of neighboring northern Mali. (AP Photo / Hakon Mosvold Larsen / NTB scanpix) NORWAY OUT

  • An unidentified rescued hostage receives treatment in a hospital Ain Amenas, Algeria, in this image taken from television Friday Jan. 18, 2013. Algeria’s state news service says nearly 100 out of 132 foreign hostages have been freed from a gas plant where Islamist militants had held them captive for three days. The APS news agency report was an unexpected indication of both more hostages than had previously been reported and a potentially breakthrough development in what has been a bloody siege. (AP Photo/Canal Algerie via Assiaciated Press TV) ** TV OUT ALGERIA OUT **

  • Residents of Ain Amenas, Algeria, gather outside the hospital trying to get information concerning relatives wounded during the terrorist attack at the gas plant, Friday, Jan. 18, 2013. The hostage crisis in the remote desert of Algeria is not over, Britain said Friday, after an Algerian raid on the gas plant to wipe out Islamist militants and free their captives from at least 10 countries unleashed bloody chaos. (AP Photo/Anis Belghoul)

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