BAGHDAD (Reuters) - The U.S. military is sending 3,000 soldiers home from Diyala province, the second large unit to leave Iraq as troop levels are cut after a 30,000-strong “surge” earlier this year.

U.S. soldiers walk through dust in front of their base after a patrol in Baquba June 26, 2007. The U.S. military is sending 3,000 soldiers home from Diyala province, the second large unit to leave Iraq as troop levels are cut after a 30,000-strong "surge". REUTERS/Goran Tomasevic

Soldiers from the 3rd Brigade, 1st Cavalry Division, will not be replaced by a new unit when they leave the ethnically and religiously mixed province north of Baghdad by January, military officials said on Tuesday.

Instead, troops from the larger 4th Striker Brigade Combat Team, 2nd Infantry Division, located near Baghdad, will take over the area, said military spokeswoman Major Peggy Kageleiry.

“Most of the (brigade) will be home by Christmas and indeed a few people have left,” Kageleiry said.

About 2,200 Marines from the 13th Marine Expeditionary Unit left western Anbar province in late September under President George W. Bush’s plan to cut troop levels in Iraq.

Bush poured in an extra 30,000 troops from mid-February in a bid to stop Iraq spiraling into sectarian civil war. There are around 162,000 U.S. soldiers in Iraq, the Pentagon said.

U.S. and Iraqi officials say the troop “surge”, more efficient Iraqi security forces and the use of neighborhood patrols have helped bring about sharp falls in U.S. military and Iraqi civilian casualties in the past two months.

Kageleiry said the overall number of troops in Diyala, where violence spiked when al Qaeda fighters were driven out of western Anbar province earlier this year, would not decrease.

With the daily toll of suicide bombs, sectarian killings and other violence slowing, General David Petraeus, the U.S. commander in Iraq, plans to pull out five of his 20 brigades in Iraq by July 2008.

“The security situation in northern Iraq has improved exponentially,” Kageleiry said. “The ultimate goal is to transition Iraqi security forces to be able to provide security to citizens of Diyala independent of coalition forces.”

Mortar and rocket attacks dropped to their lowest level in October since February 2006. In Baghdad, Iraqi military officials plan to reopen some streets and hope to end a joint U.S.-Iraqi security operation in Baghdad soon.

Despite the security improvements, 2007 has been the deadliest year for U.S. soldiers since the 2003 invasion to topple Saddam Hussein, with 857 killed so far.

The U.S. military says drawdowns in troops will occur only where security conditions allow. Other areas in northern Iraq such as Mosul, Iraq’s third largest city, often suffers fierce fighting between security forces and al Qaeda.

The troop surge and improved security were meant to pave the way for political progress on legislative benchmarks designed to promote national reconciliation, but progress has been slow.