Syrian insurgents killed 56 government soldiers during an assault that led to their capture of an air base in the northwest of the country, the Syrian Observatory for Human Rights monitoring group said on Thursday.
An alliance of insurgents including al Qaeda's Syria wing Nusra Front seized the Abu al-Duhur military airport on Wednesday as Syrian troops withdrew from their last major stronghold in Idlib province.
The Observatory's director Rami Abdulrahman said the 56 soldiers were either killed in fighting or killed afterwards.
Dozens of soldiers were also reported missing and insurgents took around 40 others captive, he said, citing sources on the ground in Syria.
Asked about the report, a Syrian military official said the army was not commenting on the situation and reiterated a previous statement that the base had been evacuated on Wednesday.