Lavrov said in a televised news conference on Monday that the countries calling for action "cannot provide evidence" of the chemical weapons attack , and have assumed the role of "both investigators and the UN Security Council" in probing the incident.
Lavrov blamed Syrian opposition for manipulating reports of the attack in order to derail a peace conference on Syria.
France, Britain, Israel and some US congressmen have said military action against President Bashar Assad's government should be an option if it has used such weapons. A U.N. team is on the ground investigating the Aug. 21 attack that left hundreds dead.
Lavrov also warned the West against intervening militarily in the Syrian conflict without the approval of the UN Security Council, saying such action would violate international law.
"Using force without the approval of the UN Security Council is a very grave violation of international law," he told reporters.
He said the West was currently moving towards "a very dangerous path, a very slippery path".
NJF/NJF