MOSCOW — Western nations that are calling for military action against Syria have no proof the Syrian government is behind the alleged chemical weapons attack, Russian Foreign Minister Sergei Lavrov said Monday.

France, Britain, Israel and some U.S. congressmen have said military action against Syrian President Bashar Assad’s regime 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 said in a news conference that the countries calling for action have assumed the role of “both investigators and the U.N. Security Council” in probing the incident.

“They cannot produce evidence, but keep on saying that the `red line’ has been crossed and they cannot wait any longer,” he said.

Lavrov likened the situation in Syria to the run-up before the 2003 military operation in Iraq. He warned against military intervention in Syria, saying “the use of force without a sanction of the U.N. Security Council is a crude violation of the international law.”

Russia’s foreign policy chief also blamed the Syrian opposition for manipulating reports of the attack in order to derail a peace conference on Syria. Lavrov said Russian and U.S. experts were days away from meeting up to arrange a peace conference in Geneva on Syria.

“This hysteria will definitely work against this meeting,” he said.

In Syria, a U.N. vehicle belonging to a team investigating the alleged use of chemical weapons in Damascus was shot at by snipers Monday as experts were moving to investigate the incident that left hundreds dead.

“I don’t have any doubts that it will be said that the firing came from the other side. But all this is moving in one direction and doesn’t inspire optimism,” Lavrov said.

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