Amnesty International says it supports the claims of a Canadian man who alleges he has been tortured while behind bars in the North African country of Mauritania.

Alex Neve, head of Amnesty's Canadian branch, said he believes the torture allegations made by 24-year-old Aaron Yoon, who has been in a Mauritanian prison since 2011 on terror-related charges, including a link to the January attack on an Algerian gas plant.

Neve said that Yoon also told Canadian government officials who visited him in prison that he had been tortured, so he wants to follow up with Ottawa about what they are doing about his case.

The Foreign Affairs Department declined comment Tuesday.

Allegations 'vivid and detailed'

Neve has just finished a 10-day trip to Mauritania where he repeatedly met Yoon, who denies all the terrorism charges against him and says he was tortured.

"I would say that his torture allegations were vivid and detailed," Neve told The Canadian Press on Tuesday, shortly after he arrived back in Canada.

"They're certainly credible and completely consistent with the wider pattern that we've known to be the case for quite some time in Mauritania. Torture is very commonplace during the early period of detention."

Yoon is accused by prosecutors of having links to the attackers who targeted an Algerian gas plant in January in an incident that ended with the deaths of the 37 hostages and 29 attackers.

The attackers included two Canadians from London, Ont., who were found dead at the plant after it was stormed by Algerian troops.

Mauritanian prosecutors want to increase Yoon's sentence to 10 years because of what they say are his links to the Algerian plot.

Last July, Yoon was sentenced to two years in prison after being convicted of having ties to a terrorist group and of posing a danger to national security.

Yoon is accused of travelling to Morocco with Ali Medlej and Xris Katsiroubas, all of whom went to the same high school in London, Ont. The RCMP confirmed that Medlej and Katsiroubas were among the dead attackers found in the Algerian plant.

Yoon has said he went to the region for religious study and that he didn't know how Medlej and Katsiroubas had become linked with militants.

Aaron Yoon interview

Watch Adrienne Arsenault's interview with Aaron Yoon.  Yoon, who spoke to the CBC via cellphone earlier this year, said he had been wrongfully accused, beat up and tortured.

Yoon said he heard about the Algerian gas plant attack while in prison, and that it was "news" to him at that point, Neve said.

Yoon was arrested in December 2011 in the capital, Nouakchott, by police. He was pursuing religious studies in an outlying area about 100 kilometres from the capital, he told Neve.

He told Neve and other Amnesty researchers that he signed a bogus confession after a second round of torture by police. Neve also said he was able to name the man he said took the lead in the two rounds of beatings he endured in the days after he was arrested.

"The first time was just a free-for-all of beatings," said Neve, describing how Yoon said he was kicked, punched and beaten with a baton for about an hour before losing consciousness.

On the second occasion, Yoon's hands and feet were handcuffed behind his back and tied to each other and then tightened, said Neve. Defenceless and lying stomach down in a bow shape, Yoon was beaten for about 20 minutes, he said.

"That's what broke him," said Neve. "He was prepared to sign anything. And he did."

Court decision pending

Yoon appeared briefly in a Mauritanian court last month and was told that a decision on whether to increase his sentence to 10 years would be handed down on June 9. But the decision was postponed, said Neve.

Neve said the abuse Yoon endured was part of a systematic pattern inflicted on prisoners by Mauritanian security officials.

In a report released just last month, Amnesty documented a broader pattern of that type of abuse by Mauritanian officials, all in the name of combating a rise of terrorist activity in North Africa.

The report says that after Mauritania adopted a new anti-terror law in July 2010, security forces were given extra powers to detain suspects in their battle against organizations such as al-Qaeda in the Islamic Maghreb.

"Torture as a means of investigation and repression is deeply anchored in the culture of the security forces and is condoned by state authorities at the highest level," the report said.

"Amnesty International is also deeply concerned that the courts have declared that 'confessions' extracted under torture and other ill-treatment are admissible as evidence, even if they are subsequently retracted."

Amnesty said it based its findings on interviews with dozens of current and former detainees.

An anonymous source, identified as a Mauritanian judicial official, told The Associated Press earlier this year that Yoon had confessed to terrorism.

The Amnesty report said torture methods used included cigarette burns, electric shocks, sleep deprivation, hair pulling and threats to families.

The report also paints a bleak portrait of living conditions inside one large prison.

Some prisoners slept on mattresses on the floor, while others had to make do with rags on the floor, "surrounded by vermin and ridden with fleas," the report said.

"Men pressed up against one another in stifling heat, and are rarely able to leave their cells or breathe fresh air. The only opportunity prisoners have to stretch their legs is in the narrow corridors which are littered with refuse."