Last U.S. "surge" brigade begins leaving Iraq

BAGHDAD (Reuters) - The U.S. military has begun withdrawing from Iraq the last of the five additional combat brigades that were deployed to the country in 2007, a U.S. military spokesman said on Tuesday.

The final "surge" brigade would leave Iraq by the end of July, the spokesman said. That was in line with plans by General David Petraeus, the commander of U.S. forces in Iraq, who has said lower levels of violence would allow the reductions.

U.S. troop levels are a key issue in the November presidential election.

The U.S. military had 20 combat brigades in Iraq at its peak in 2007, with troop levels around 160,000-170,000. Numbers will fall to about 140,000 once the final "surge" brigade departs.

"Elements of the fifth surge brigade have already begun redeploying, so, by the end of July, we will be at 15 combat brigade teams in Iraq," the military spokesman said.

He declined to identify the brigade or give its location for security reasons.

U.S. President George W. Bush sent an extra 30,000 soldiers to Iraq last year to stop savage sectarian violence between majority Shi'ites and minority Sunni Arabs that threatened to tip the country into all-out civil war.

The troop buildup was credited with helping improve security. Other factors were a rebellion by Sunni Arab tribal leaders against al Qaeda and a ceasefire by anti-American Shi'ite cleric Moqtada al-Sadr.

The additional brigades have redeployed out of Iraq over the past six months.

In late May, Petraeus said he expected to recommend resuming withdrawals after a 45-day freeze to take stock of conditions.

Democratic presidential candidate Barack Obama has called for the removal of U.S. combat troops from Iraq within 16 months of taking office should he win the election.

Republican candidate Senator John McCain says the U.S. troop buildup has helped boost stability in Iraq. He has criticized Democrats' promises for a quick withdrawal as "reckless".

(Reporting by Dean Yates, Editing by Ralph Boulton)