GENEVA (REUTERS, ASSOCIATED PRESS) - Any US military action taken in response to apparent chemical weapons attacks in Syria would need to be approved by the UN Security Council, international envoy Lakhdar Brahimi said on Wednesday.

"I think international law is clear on this. International law says that military action must be taken after a decision by the Security Council. That is what international law says," he told a press conference in Geneva.

"I must say that I do know that President Obama and the American administration are not known to be trigger-happy. What they will decide I don't know. But certainly internationl law is very clear."

Brahimi told reporters that evidence suggests that some kind of chemical "substance" was used in an attack that killed hundreds of people.

"It does seem like some kind of substance was used," that killed hundreds of people, he said.