Brahimi spoke to reporters in Geneva as a U.N. inspection team was investigating the alleged poison gas attack near Damascus on Aug. 21 and momentum built for Western military action against Syrian President Bashar Assad's regime in the civil war that he called the most serious crisis facing the international community.
Brahimi also said that any U.S.-led military action must first gain approval from the 15-nation Security Council, whose five permanent members — Britain, China, France, Russia and the United States — each have veto power.
"International law says that any military action must be taken after" Security Council approval, he said. But, he added, President Barack Obama's administration is "not known to be trigger-happy.