The US is to supply direct military aid to the Syrian opposition for the first time, the White House has announced.

President Obama made the decision after his administration concluded Syrian forces under Bashar al-Assad were using chemical weapons, a spokesman said.

Ben Rhodes did not give details about the military aid other than to say it would be "different in scope and scale to what we have provided before".

The US had warned any use of chemical weapons would cross a "red line".