BAGRAM AIR FIELD, Afghanistan -- The first troops to leave Afghanistan as part of the U.S. drawdown handed over their slice of battlefield Wednesday to a unit less than half their size and started packing for home.

When the 650 members of the Iowa National Guard's 1st Squadron, 113th Cavalry Regiment arrived in Afghanistan in November, bases didn't have enough housing, translators were in short supply and chow halls were packed.

Commanders were using a buildup of 33,000 extra troops for a major push that they said would turn the tide of the war against the Taliban insurgency.

Nine months later, it still is now known if that push has succeeded, but the pullback has begun. Although major combat units are not expected to start leaving until late fall, two National Guard regiments comprising about 1,000 soldiers are withdrawing this month -- the Iowa soldiers from Parwan province in eastern Afghanistan and the other group from the capital, Kabul.

U.S. President Barack Obama announced last month that he would pull 10,000 of the extra troops out in 2011 and the remaining 23,000 by the summer of 2012.

Three hundred soldiers will take over from the 650 departing troops who oversaw security in Parwan, including the area outside the main U.S. military base at Bagram.

In a ceremony at Bagram marking the transfer, a speaker read out a list of the 113th's accomplishments: 14 high-value targets killed or captured, the largest homemade explosives lab in Parwan discovered and dismantled, 52 consecutive days of keeping insurgent fire out of the Bagram base, 3,800 combat missions completed, 400 Afghan police officers trained and a coordination center built.

She also read out the cost: One soldier died when a team helicoptered into a firefight to aid a downed pilot.

The commander of the outgoing unit said he expects his successors to be able to build on his unit's accomplishments.

"They may not be as robust as us, or have as many as us, but they certainly will have the ability to secure the Bagram security zone," said Lt. Col. David Updegraff. He said he felt he could have completed his mission with a smaller force, but that the extra numbers made it significantly easier.

Some in the 113th said 650 soldiers were barely enough.

"Most of our platoons were short-manned quite often. We were running with the minimum amount that we safely can. And they were running long missions, long days," said Staff Sgt. Brian Pals, 34, of Hartley, Iowa.

Outgoing soldiers said they needed all their numbers to do the type of intensive training and mentoring called for by a strategy focused on building up the Afghan forces.

They had to spend extra time demonstrating techniques to Afghan police officers who were illiterate and had to teach Afghan soldiers basic map-reading skills.