WASHINGTON — Two Senate committees want to investigate whether U.S. intelligence accurately pointed to banned weapons in Iraq as claimed by the Bush administration in going to war, senators said Sunday.

More than 11 weeks have passed without conclusive evidence of an Iraqi program to develop weapons of mass destruction, senators said, and it's time to investigate whether intelligence reports saying so were correct.

An investigation doesn't mean senators think that something was done incorrectly, Sen. John Warner, R-Va., chairman of the Armed Services Committee, said on CNN's "Late Edition."

"By the fact that we're just investigating it, should not in any way indicate that we're putting any credibility doubt against" the CIA or the Bush administration, Warner said.

He said his committee and the Senate Intelligence Committee might look jointly into the situation.

One member of the Intelligence panel, Sen. Bob Graham, running for the Democratic presidential nomination from Florida, went further than other senators in declaring on CNN that the government might have willfully distributed erroneous information on Iraq's arsenal.

"If we don't find these weapons of mass destruction, it will represent a serious intelligence failure or the manipulation of that intelligence to keep the American people in the dark," Graham said.

The Bush administration's main argument for the Iraq invasion was that deposed President Saddam Hussein held chemical and biological weapons and possibly was developing nuclear weapons. All were banned to Iraq under sanctions imposed by the United Nations after Iraq invaded neighboring Kuwait and by subsequent U.N. resolutions.