Updated

British Foreign Office official Hugh Robertson has accused the government of Syrian President Bashar Assad of effectively murdering a U.K. doctor held in Syrian custody.

Robertson said in televised comments Tuesday that there was no excuse for "Syrian authorities who have, in effect, murdered a British national who was in their country to help people who were injured during their civil war."

Dr. Abbas Khan, a 32-year-old orthopedic surgeon from London, was seized by government troops in Aleppo in November 2012 after he entered the country on a humanitarian mission.

The Foreign Office said earlier that it was "extremely concerned" by reports Khan had died in detention. There was no immediate response from the Syrian government to Associated Press queries about the case.