WASHINGTON (Reuters) - Calling for the impeachment of U.S. President George W. Bush and Vice President Dick Cheney, Cindy Sheehan and 45 fellow Iraq war protesters were arrested on Monday after they refused to leave a U.S. lawmaker’s office and adjoining hallway, authorities said.

Peace activist Cindy Sheehan takes part in a march to deliver more than 1,000,000 signatures to Congressman John Conyers, appealing to him to begin impeachment proceedings against U.S. President George W. Bush and Vice President Dick Cheney, in Washington July 23, 2007. REUTERS/Joshua Roberts

Before police escorted her away, Sheehan, who emerged as a leading peace activist after her son Casey was killed in Iraq in 2004, announced what she had earlier suggested -- that she would be a candidate for Congress next year.

Sheehan said she would challenge House of Representatives Speaker Nancy Pelosi, a California Democrat. Pelosi has refused calls to start impeachment of Bush and Cheney for what critics charge was misleading the United States into war.

The new Democratic-led Congress has been hit with approval ratings of less than 25 percent largely because of its failure to deliver on a campaign vow to withdraw troops from Iraq.

Sheehan and fellow protesters were led away in plastic handcuffs after they refused to heed repeated calls by Capitol Police to depart the office of Democratic Rep. John Conyers of Michigan, and a hallway outside his office.

“What do we want? Impeachment. When do we want it? Now,” Sheehan and others chanted while seated on the floor of Conyers’ office following her private meeting with him.

A spokeswoman for Capitol Police said the 46 protesters were being charged with disorderly conduct, a misdemeanor, and were likely to be released within hours after processing.

Conyers had raised the possibility of impeaching Bush more than a year ago while Republicans were in charge of Congress.

But Pelosi rejected the idea during last year’s campaign that saw Democrats win control of the House and Senate, saying she wanted to concentrate efforts on ending the war.

“The speaker is focused on changing course in Iraq by bringing our troops home safely and soon and refocusing our effort on protecting Americans from terrorism,” said Brendan Daly, Pelosi’s press secretary.

When Sheehan and others arrived on Capitol Hill they were confronted by a number of backers of the war. One held a sign reading, “Patriots want victory in Iraq.”