Amnesty International says Syrians detained during a year-long uprising against President Bashar al-Assad's rule have been subjected to widespread torture that amounts to crimes against humanity.

The London-based human rights group issued a report Wednesday based on interviews with 25 Syrians who said they endured torture in various detention centers before fleeing across the border to Jordan.

Neil Sammonds, the group's Syria researcher, told VOA the report documents 31 methods of torture meted out by security forces, army and pro-government armed gangs.

“Some of these forms of torture we see a kind of resurgence of methods and levels of abuse which we haven't really seen since the dark days of the 1980s when Bashar al-Assad's father, Hafez, of course was in power.”

He said the number of people who died under “highly suspicious circumstances” while in detention in Syria has been increasing, with 88 cases in the first five months of the uprising, and now a total of more than 270 a year after protests began.

“Definitely the human rights situation is worsening in the country, and we continue to call for the situation there to be referred to the prosecutor of the International Criminal Court because crimes against humanity are taking place.”

Sammonds also said the group has second-hand information about cases of abuse by the Syrian opposition, but that they are “very small” compared to the abuses of Mr. Assad's government.

In Syria, government forces have recaptured control of the northern city of Idlib near the Turkish border. Several days of assaults pushed hundreds of military defectors out of Idlib – a major operational base they had held for months.

U.N.-Arab League envoy Kofi Annan, who met with Mr. Assad in Damascus earlier this week, said Tuesday he had made “concrete” proposals to the Syrian leader on ways to halt the attacks and secure humanitarian access to cities where thousands have been killed in the past year. A spokesman for the envoy ((Ahmad Fawzi) said “their responses are being considered.”

Human Rights Watch said Tuesday Syrian forces have planted internationally banned anti-personnel mines near the borders with Lebanon and Turkey in recent months.

White House Press Secretary Jay Carney said Tuesday the Obama administration is not surprised by “dangerous, militaristic behavior” by Mr. Assad's government.

“After all, they have been waging war on their own people for many, many months now. And the toll of that war continues to increase. It is writing, the Syrian regime, is writing its own horrific page in history and the history of its country, and the history of the region.”

U.N. officials estimate that 7,500 people have died in the year-long violence.