EU foreign ministers are discussing UK and French calls to ease sanctions so Syria rebels can be supplied with arms.
France and the UK argue that the move would push Damascus towards a political solution.
However, several EU states are totally opposed to ending the arms embargo, which expires on 31 May.
Meanwhile French Foreign Minister Laurent Fabius said there were "growing suspicions" of "localised" chemical weapons use in Syria.
Mr Fabius said the evidence needed "very detailed verification".