The United States and the U.K. have suspended supplies of non-lethal military aid to rebels in northern Syria, citing concerns that the equipment could end up in the hands of al-Qaeda-linked fighters, officials said Wednesday.

An American official told the Associated Press that the U.S. would stop providing supplies like night vision goggles and communications equipment, after ultraconservative opposition fighters seized a base from the more moderate, Western-backed groups amid ongoing infighting.

The suspension does not affect humanitarian aid, and the U.S. will continue to supply rebels in the south of Syria with non-lethal aid via Jordan.