CIA-coordinated military aid for rebels in northwest Syria has been frozen since they came under major Islamist attack last month, rebel sources said, raising doubts about foreign support key to their war against President Bashar Assad.

Rebel officials said that no official explanation had been given for the move this month following the jihadi assault, though several said they believed the main objective was to prevent arms and cash falling into Islamist militant hands. But they said they expected the aid freeze to be temporary.

The halt in assistance, which has included salaries, training, ammunition and in some cases guided anti-tank missiles, is a response to jihadi attacks and has nothing to do with U.S. President Donald Trump replacing Barack Obama in January, two U.S. officials familiar with the CIA-led program said.