The body of a British doctor who died in Syrian custody has been handed over to his family and British officials in Lebanon as relatives said the regime killed him.
Human Rights Watch also piled the pressure on Syrian authorities on Saturday, accusing the government of "wreaking disaster" in deadly air raids on second city Aleppo.
On the diplomatic front, peace envoy Lakhdar Brahimi held talks with the foreign minister of Syria's ally Iran, after negotiators failed to agree on a role for Tehran in a peace conference.
The International Committee of the Red Cross (ICRC) said Doctor Abbas Khan's body was brought out of Syria and given to his family and British officials in Beirut.
"The British embassy in Lebanon is expected to rapidly fly the body to London," a statement said.
Khan's mother, Fatima, was at a Beirut hospital morgue to receive his remains and accused Syrian authorities of killing him.
Britain also holds Damascus responsible for the death of the 32-year-old orthopaedic surgeon.
Khan, a volunteer with Human Aid UK, had travelled to Aleppo last year to help civilians when the regime arrested him.
Syria said this week that Khan had been found "hanging" in his cell, where he was being held for "unauthorised activities," and that he had committed suicide.
But his mother told the BBC that Syrian security authorities had killed him.
"He was so good to humanity. How could they kill a humanitarian aid worker? He did not treat any terrorists, he treated only women and children, he told me."
While he was in detention, Syrian television had described Khan as a "terrorist," the term it uses to brand its opponents.
Syria's 33-month war has killed an estimated 126,000 people, and Human Rights Watch says air force bombing raids on Aleppo have left hundreds more dead in the past month.
"The Syrian air force is either criminally incompetent, doesn't care whether it kills scores of civilians - or deliberately targets civilian areas," said HRW's Ole Solvang.
The statement comes six days after the launch of a massive aerial campaign against rebel-held areas of Aleppo, during which activists said TNT-packed barrels were used.
The violence comes despite preparatory talks for a long-awaited Syria peace conference slated to take place in Switzerland on January 22.
The conference organised with backing from Russia and the United States is due to bring together opposition and regime representatives.
