WASHINGTON (AP) – The Senate on Friday voted unanimously to confirm the nomination of Army Lt. Gen. David Petraeus to command American troops in Iraq at a time when President Bush is building up American forces there.

Mr. Petraeus’ 81-0 approval was in contrast to the widespread public and congressional opposition to Mr. Bush’s plan to send 21,500 more troops to Iraq. Congress is moving toward votes in coming weeks on nonbinding resolutions opposing the troop build up.

Public sentiment has turned strongly against a war that has dragged on for nearly four years with more than 3,000 American dead and violence unabated by insurgents and sectarian militias.

“It’s going to be an extremely complex mission,” Senator Warner, a leading Republican on defense issues, said of the task awaiting Mr. Petraeus.

Mr. Warner, who has crafted a bipartisan resolution saying the Senate opposes the troop increase, said he hopes American troops will be instructed that “wherever possible, the Iraqis should bear the brunt of the sectarian violence.”

In testimony to Congress this week, Mr. Petraeus said the situation in Iraq is “dire” but said he believed Mr. Bush’s strategy would work – assuming the Iraqi government provided additional troops and helped crack down on militias.

Mr. Petraeus, who will replace Army Gen. George Casey. is just one of the new faces Bush is bringing to his team of top military and diplomatic officials in Iraq and the Middle East. He has already replaced Secretary Rumsfeld with Secretary Gates at the Pentagon, and is changing the top military commander in the Middle East and the American ambassador to Iraq.

Mr. Petraeus, 54, has served two previous yearlong tours in Iraq as commander of the 101st Airborne Division during the invasion in March 2003 and as commander of the training program for the Iraqi Army in 2004-05.

Following the Nov. 7 elections, Mr. Bush announced he would change his strategy in Iraq, including deployments of the additional troops.

“We’ll now have our very best general in charge of the operations in Iraq,” Senate Republican Leader Mitch McConnell, R-Ky., said in a statement. “If it can’t be done under Gen. Petraeus, then it cannot be done at all. We ought to give him a chance to succeed.”

Next Tuesday, the committee plans to hear from Navy Adm. William Fallon, Mr. Bush’s pick to replace Gen. John Abizaid as the top commander in the Middle East. Casey, nominated to be the next Army chief of staff, is expected to testify on Feb. 1.

Mr. Fallon is expected to testify next Tuesday before the Senate Armed Services.