BELGRADE, Serbia (AP) — U.S. Senator John McCain has accused Russia of having cooperated with Syria in a chemical weapons attack that has killed more than 80 people, including more than a dozen children.

The Republican senator said Monday at a press conference in Belgrade that he believes "the Russians knew about chemical weapons because they were operating exactly from the same base."

He says "I hope that this behavior by Syria, in what clearly is cooperation with Russia and Syria together, will never happen again."

McCain says the U.S. should take out Syria's air force as part of stopping Syrian President Bashar Assad from repeating such attacks in the future.

He says "the United States should first tell Russia that this kind of a war crime is unacceptable in the world today."