SCHOFIELD BARRACKS — The commanding general of the 25th Infantry Division will head to northern Iraq in October with a shrinking number of U.S. forces and as the landscape has changed from security and raids to stability and reconstruction.

Maj. Gen. Robert Caslen Jr. will have three combat brigades — including the 3,500-soldier 3rd brigade at Schofield — under his command in the Pennsylvania-sized region of northern Iraq.

By comparison, a predecessor from Schofield had as many as five combat brigades on a 2006-07 deployment to the same region.

But Iraq is a changing place, with security on the upswing.

A long-term security agreement is being worked out with the Iraqi government that could see American troops withdraw from many Iraqi cities and remain more on big bases, starting next June.

Gen. David Petraeus, the top U.S. commander in Iraq, told the Financial Times that U.S. troops could leave Baghdad by July.

"The number of attacks in Baghdad lately has been ... probably less than five (a day) on average, and that's a city of 7 million people," Petraeus said.

Caslen said yesterday he's OK with the smaller force he'll have in northern Iraq.

"When you have a security situation that's got security levels the way they were back in 2004 (when violence was lower), you really don't need that large of a force to provide security," Caslen said.

He also said Iraqi security forces are correspondingly becoming more capable.

Caslen, who took over command of the 25th Infantry Division in May, talked about the upcoming deployment yesterday at a big mission rehearsal exercise at Schofield.

More than 3,000 personnel are taking part in the exercise that started on Aug. 25 and ends tomorrow. A series of tent-like structures is set up inside the 1st Lt. Nainoa K. Hoe Battle Command Training Center at Schofield, named for the 1995 Kamehameha Schools graduate who was killed by a sniper in Iraq in 2005.

In Iraq, Caslen will have under his command the 3rd brigade from Schofield; the 1st Stryker brigade out of Fort Lewis, Wash.; and the 3rd brigade of the 1st Cavalry Division out of Fort Hood, Texas.

Additionally, he'll have aviation, engineer and artillery fire brigades, and some smaller units.

The 4,000-soldier Stryker brigade out of Schofield, meanwhile, is about eight months into an anticipated 15-month deployment to Taji and Tarmiyah just north of Baghdad.

A change in deployment policy after the Stryker soldiers left means the 3rd brigade likely will be in Iraq for about a year.

Caslen went on a two-week reconnaissance mission to northern Iraq at the end of June, officials said. He will be based out of Contingency Operating Base Speicher near Tikrit, but officials said the locations for the troops under his command still are being determined.

About 1,000 soldiers with the division headquarters are part of the deployment. Final training ended last week for the 3rd brigade from Schofield at the National Training Center in California, and the soldiers are on two weeks of leave.

Security challenges remain in Iraq in Mosul and still-restive Diyala province northeast of Baghdad, where al-Qaida in Iraq still has a foothold and sectarian violence continues in the mixed region of Sunnis, Shiites and Kurds.

Caslen, who has deployed to Afghanistan before, but will be on his first tour to Iraq, said the possibility of a June withdrawal to bases the U.S. has in Iraq will be determined by a new status-of-forces agreement.

A United Nations mandate that provides the basis for the U.S. to be in Iraq expires on Dec. 31.

In a scenario that Caslen participated in Tuesday during the mission rehearsal exercise, a Shiite mosque was blown up in Muqdadiyah in Diyala province. Intelligence indicated that al-Qaida in Iraq was responsible.

"So what we're doing now as senior leaders is, we're talking to the provincial governor, who is a Shiite, and encouraging him to restrain the response, particularly for the Shiite community," Caslen said.