Defense Secretary Leon E. Panetta arrived here today to join Army Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, in ceremonies marking the end of the U.S. military mission in Iraq.

The secretary and chairman, along with Army Gen. Lloyd Austin, commander of U.S. Forces Iraq, and Ambassador James Jeffrey, will lead the U.S. delegation at the ceremony.

"This will be an historic moment where we basically enter a new chapter in Iraq in which we deal with them in a way that represents the kind of normal relationship we have with other countries" in the region, Panetta told reporters traveling here with him.

The secretary, who arrived here after visits to Djibouti in the Horn of Africa and Afghanistan, will join U.S. and Afghan officials in highlighting the successes made here and the service and sacrifice over the past eight years that has made it possible.

As they encase the U.S. Forces Iraq colors and officially bring the mission here to an end, Panetta said the United States will forge the next phase of a long-term relationship with Iraq.

The ceremony will signal that "this is not the end," a senior defense official traveling with Panetta said. "We are changing the nature of our relationship with Iraq, but [will send a signal of] our commitment to continuing this strategic partnership with them."

The secretary is also scheduled to meet with about 80 of the 5,500 U.S. troops still in Iraq as the last days of the drawdown continue through Dec. 31 to thank them personally for their contributions.

This is down from 144,000 troops who were on the ground when President Barack Obama took office.

Panetta noted the Herculean effort that has transferred hundreds of bases and infrastructure to the Iraqis and removed thousands of troops and millions of pieces of equipment from Iraq.

"It was a tremendous effort," he said, commending Austin and his team for "the great work they did in making this happen."

Panetta will present awards to Austin and Jeffrey during ceremonies closed to media coverage.