Aaron Yoon, 24, reportedly had travelled to Morocco with two Canadians accused of taking part in the terror attack on a BP-operated natural gas plant in southeastern Algeria earlier this year.
Mauritanian authorities say Yoon had ties to al-Qaida's affiliate in Africa — al-Qaida in the Islamic Maghreb, or AQIM.
"This Canadian citizen stated to investigators that he had come from Morocco to study the Qur’an and Islamic law before being indoctrinated by salafist jihadists who recruited him to join AQIM in the north of Mali," said a Mauritanian judicial official who spoke on condition of anonymity because he wasn't authorized to speak to journalists.
CBC has reported that Yoon has denied involvement in terrorist activities.
Yoon was convicted last July on charges of having ties to a terrorist group and of posing a danger to national security, the Mauritanian official said.
The Jan. 16 attack and four-day siege on a gas facility in southern Algeria ended with the deaths of 37 hostages and 29 terrorists.
Chad's government claimed that the mastermind of the attack, Moktar Belmoktar, has been killed in fighting in northern Mali, but the claim has not been independently verified.
The Canadian government has said its officials continue to provide assistance to Yoon as they would for any Canadian detained abroad.
"This assistance should not be construed as a belief of his guilt or innocence," a spokesman for Diane Ablonczy, Minister of State of Foreign Affairs, has said.
CBC News has reported that Yoon said the Canadian government has failed to assist him.
The public broadcaster aired excerpts of an interview last week with a man it said was Yoon speaking from prison.
The man claimed he had been tortured and beaten behind bars, and denied being involved in terrorist activities.
He also told CBC he didn't know how the two Canadians killed in Algeria earlier this year had become linked with militants.
Yoon is reported to have travelled overseas with Ali Medlej and Xristos Katsiroubas, the two men whose bodies were found at the site of January's Algerian gas plant siege. All three men were from London, Ont.
RCMP were called in to help Algerian authorities with their investigation of the siege.
Police in Canada held a news conference last week saying investigators are continuing to gather evidence and determine the circumstances that led to Medlej and Katsiroubas departing Canada.
The two men are believed to have played key roles in the January attack.
Police have asked members of the public to contact them if they have any information about individuals leaving Canada to take part in terrorism plots.
Officials have released no other details for fear it could end up compromising the investigation.
-- With files from The Canadian Press
Also on HuffPost