Egypt's ambassador to Canada said Tarek Loubani and John Greyson could conceivably be freed before the end of the 15-day period that prosecutors said they were ordered detained.
"Technically it is possible, because these are maximum (detention) times allowed by the law," ambassador Wael Aboulmagd said in an interview with The Canadian Press.
"I think the first period will be four days, and then ... the prosecutor decides if he needs more time."
Aboulmagd stressed, however, that under Egypt's judicial system, he could not interfere in the process, and that it would be entirely up to prosecutors to decide whether to release the men.
Loubani, a doctor from London, Ont., and Greyson, a Toronto filmmaker, were detained Friday by Egyptian police.
Friends and family say they were in Cairo after making an unsuccessful attempt to enter Gaza, where Loubani teaches emergency medicine and Greyson was exploring the prospects of making a documentary.
Canadian consular officials were expected to meet with the two men on Thursday, along with a lawyer from the Shalakany law office, hired by their families.
The Egyptian embassy in Ottawa has received more than 600 emails and phone calls from supporters of the two Canadians since their detention, Aboulmagd said.
By Wednesday morning, more than 40,000 people had also signed a petition at change.org, demanding the men be released immediately, while thousands have made phone calls to Canadian government officials and the Egyptian embassy, said family friend Justin Podur.
"This outpouring of support for Tarek and John is heartening and inspiring," Podur said in a statement.
The public prosecutor's office in Cairo says the men face a range of accusations, including threatening security and social peace, belonging to an armed gang and being in possession of firearms, ammunition and explosives.
The accusations are "wide-ranging, far-fetched and outright bizarre," said Podur.
Canada's embassy in Egypt reopened Wednesday after days of bloody clashes on the streets of Cairo. But just how long the embassy's doors will stay open remains unclear.
The embassy offices were closed last week over concerns about staff safety amid growing unrest in the Egyptian capital.
And because security in the vicinity remains volatile, the embassy could be closed again at any time.
"For security reasons, the Embassy of Canada in Cairo is subject to sporadic closures on short notice," says a statement on the foreign affairs department's website.
"The ability to provide consular services may be limited due to unpredictable security and the curfew imposed by Egyptian authorities."
The department urges Canadians against travelling to Egypt, but also suggests that Canadians who are already there should leave.
"If you are currently in Egypt, consider whether you have a pressing need to remain," says a travel advisory.
Street battles between Egyptian security forces and supporters of ousted President Mohammed Morsi that erupted a week ago have claimed nearly 1,000 lives.
The violence of the last week was not some ordinary protest, such as might be seen in North America, said Aboulmagd.
"When you have large numbers of police officers shot and killed, that means you're not talking about your typical Canadian style or American style peaceful demonstration or protest," he said.
"This is significantly different. What has happened, particularly since last Friday until today, are plain and simple acts of terror."
Still, Aboulmagd referred to the violence as a "bumpy patch" on the road toward full democracy in Egypt, which he predicted would be achieved eventually if the disputing factions return to a more peaceful political process.
Canada has condemned the violence in Egypt, but government officials have gone out of their way not to assess blame.
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