ABOARD A US MILITARY AIRCRAFT: A combat brigade of 5,000 American troops may be brought home early from Iraq if an emerging trend of reduced violence holds, Defense Secretary Robert Gates said Wednesday.

Gates' acknowledgment that he is considering speeding the withdrawal of a full combat unit by the end of this year amounts to the first hint that the Obama administration might rethink its decision to keep a large residual force in Iraq and pull them out slowly.

"I think there's at least some chance of a modest acceleration" in troop withdrawal this year, Gates told reporters on his plane en route to Washington from Baghdad. His comments came after discussions with his top commanders in the war.

US officials had worried that last month's formal handover of control of Iraqi cities to Iraqi security forces might erode gains already made. But Gates said Gen Ray Odierno, the top US general in Iraq, told Gates the security situation is better than expected.

An Associated Press tally shows seven US troop deaths this month, the lowest monthly total so far for the Iraq war since it started in 2003.

The United States has about 130,000 forces in Iraq, with current plans calling for most combat forces?- or more than 100,000 troops?- to remain in the country until after Iraqi national elections in January.

It was largely because of Odierno's concerns that the coming Iraqi election would trigger a rebound in violence that President Barack Obama decided on a slow withdrawal.

Though Obama announced in February that he would end the American combat role in Iraq, officials said at the time that the president had accepted a recommendation by U.S. officials and commanders in Baghdad to maintain substantial military forces there until after the January Iraqi election to help guarantee a safe ballot. The decision disappointed many anti-war Democrats.

Under the initial plan, the United States would draw down from 14 brigades to 12 this year. The withdrawal pace would have quickened after the January election, leaving about 50,000 forces in Iraq by September of 2010.

Gates stressed Wednesday that the idea of speeding up that pace and bringing a third brigade back by the end of this year is preliminary, tied to continued good news in Iraq.

"It depends on circumstances; it may or may not happen," he cautioned.

The Iraqi government welcomed the news and said government security forces were working toward the same goal but need more arms as well as training.

"This also must coincide with the speedier training and arming of the Iraqi security forces," government spokesman Ali al-Dabbagh said. "We are ready to take over. The faster the US troops withdraw, the faster we can fill in the gaps."

The growing Iraqi role comes as violence against civilians has declined this month. At least 255 Iraqis have been killed in attacks in July. There have been only two months?- January and May of this year?- in which fewer Iraqis were killed since The Associated Press began tracking war-related fatalities in May 2006. There were 242 deaths in January and 225 deaths in May.

On average this year, at least 10 Iraqis have been killed in war-related violence each day. In 2007, during the height of Iraq's civil unrest, an average of 50 Iraqis were dying each day.

The fatality tallies are considered a minimum, based on AP reporting. The actual number is likely higher, as many killings go unreported or uncounted. The totals of civilian, Iraqi military and Iraqi police deaths are reported by police, hospital officials, morgue workers and verifiable witness accounts. Insurgent deaths are not included.

The United States is rapidly closing down the active war effort in Iraq. Many remaining troops are shifting to become backseat advisers to the Iraqi armed forces.

At the same time, Obama is more than doubling US forces in Afghanistan. His top military advisers say that fight is now the No. 1 military priority, and fighting is fierce in some districts.

Odierno told reporters that the Iraq conflict is not over, but he conceded that some of those he leads "might tell you they would rather be fighting in Afghanistan."

Continued bad blood between Iraq's Arab-led central government and the self-ruled Kurdish region in the north represents the major wild card to a faster pullout. Concern is growing that North-South tensions over land and resources could become a shooting war once US forces leave.

Gates spent much of his two-day visit in Iraq warning both sides that US forces will not be around to keep the peace forever, and he offered U.S. help to mediate.

"These are some fundamental issues and I think it's important that both the government in Baghdad and the Kurds have pursued them through political means," so far, Gates told reporters after meeting earlier Wednesday with Kurdish President Massoud Barzani in Irbil, capital of the Kurdish self-rule area.

Gates said he told his hosts that all sides had spent "too much in blood and treasure" since the 2003 US invasion to risk losing it now.