"We of course condemn in the strongest terms the attack and we call for the international community to take strong action ... But let's wait until definitive information has been drawn together before we do that, particularly by the UN inspectors," said Michael Mann, a spokesman for foreign policy chief Catherine Ashton.

Ashton is also waiting for the report before blaming the Syrian government, he said.

This is while the UN leader Ban Ki-moon said Monday that a military strike on Syria over the use of chemical weapons could worsen the country's conflict.

"We must consider the impact of any punitive measure on efforts to prevent further bloodshed and facilitate the political resolution of the conflict," Ban told a press briefing at the UN headquarters.

The US and France are pushing for punitive air strikes against the Syrian regime but want to gather international support before taking any military action.

Obama's decision on Saturday to ask Congress to authorize action against Syria lifted the threat last week of any immediate strikes against Assad's government.

The British parliament last week rejected any intervention in Syria.

NJF/NJF