A 24-year-old Canadian who was imprisoned in Mauritania over suspected links to al Qaeda in North Africa has arrived back in Canada.

Aaron Yoon, a native of London, Ont., arrived at Pearson International Airport in Toronto shortly after 2 p.m. Friday. He was escorted by RCMP officers, federal government sources told CTV.

Yoon was released from a Mauritanian jail after serving an 18-month sentence for alleged ties to an al Qaeda-affiliated group in North Africa.

Yoon was arrested in December 2011 after travelling to North Africa with two other Canadians who were believed to be involved in an attack on a natural gas plant in Algeria in January.

His friends and former high school classmates, Ali Medlej and Xristos Katsiroubas, died in the bloody attack that has been linked to members of al Qaeda in the Islamic Maghreb.

Yoon was in prison at the time of the gas plant siege, which left at least 38 hostages and 29 militants dead.

Prosecutors alleged Yoon had links to terrorist activity and played a role in the recruitment of jihadists.

Yoon has denied any links to terrorism, saying he travelled to Mauritania to learn Arabic and study the Qur’an.

A Mauritanian appeals court ordered his release earlier this month, saying he had served the duration of his reduced sentence.

Yoon’s return is considered a major opportunity for Canadian intelligence to gather firsthand information on his alleged terrorist ties. However, Yoon may not want to speak to authorities.

RCMP would not say if Yoon was detained upon his arrival in Toronto.

In response to Yoon’s return, Public Safety Canada issued a brief statement: “Security agencies take appropriate steps to keep Canadians safe.”

With files from CTV's Daniele Hamamdjian