WILMINGTON, N.C. — Four North Carolina National Guard soldiers were killed in Baghdad on the last day of regular combat operations for U.S. forces in Iraqi cities, the military said Thursday.

It was the North Carolina National Guard's largest single combat loss since World War II, said Maj. Matthew Handley a North Carolina National Guard spokesman. The deaths bring to 15 the total number of North Carolina National Guard soldiers killed in action since Sept. 11, 2001.

The Department of Defense said an improvised explosive device detonated near their vehicle, killing the four men who were assigned to the 120th Combined Arms Battalion in Wilmington.

Officials identified the men as Sgt. 1st Class Edward C. Kramer, 39, of Wilmington, Sgt. Roger L. Adams Jr., 36, of Jacksonville, Sgt. Juan C. Baldeosingh, 30, of Newport and Spc. Robert L. Bittiker, 39, of Jacksonville.

"The North Carolina National Guard and the people of our state mourn today with the families of these fine soldiers," said North Carolina National Guard commander Maj. Gen. William E. Ingram Jr. "The Guard is a very close-knit organization, and the loss of these brave men will leave a lasting impact on us all."

Three of the soldiers – Baldeosingh, Kramer and Adams – were former Marines. Kramer, a firefighter in Wilmington, was a veteran of Desert Shield and Desert Storm in 1991. He joined the National Guard in 1994 and deployed with the guard to Iraq in 2004.

His family described Kramer in a statement Thursday as "a family man who put his family first and believed in serving his country." He liked ride his motorcycle and fish.

"That's where he was most at peace - out on the beach," said firefighter Michael Bannon.

He started as a firefighter as a volunteer with the Seagate Fire Department before joining the Camp Lejeune Fire Department and finally the City of Wilmington. He recently transferred to the Sunny Point Fire Rescue.

He is survived by his wife Vicki and two daughters, 9-year-old Erica and 7-year-old Megan.

"He loved us very much and he did this for his children so they wouldn't have to," his wife said in the statement.

Adams served more than a decade as a Marine before joining the National Guard in 2006. He is survived by a wife and four children.

Baldeosingh was a graduate of Holy Trinity Catholic School in Hicksville, N.Y., who subsequently joined the Marine Corps and was stationed at Camp Lejeune. He left the Marines to take a job as sergeant of security at the Carteret General Hospital where he also assisted as a Spanish translator. He joined the National Guard in June 2008.

His family described him as "funny, kind, thoughtful, and a family oriented man who loved to watch his three daughters dance and make arts and crafts with them."

He met his wife, Rebecca Baldeosingh, at Camp Lejeune.

"He is truly an American hero. I am so proud of him for fighting for our country. He did what he wanted to do and that was to be in the military," Rebecca Baldeosingh said in a statement. "I loved him so very much. I will miss him terribly. He will forever be in my heart!"

Bittiker enlisted in the North Carolina Army National Guard in 1990. This was his third combat deployment, having served in Bosnia and Iraq in 2004.

His mother, Mary Wheat, said she talked to her son on Father's Day.

"He said it was quiet around there, but I am not sure he didn't say that so we wouldn't worry," she told The Associated Press on Thursday night.

She said her son liked to fish, cheer for the Washington Redskins and work on an old beat-up truck and Ford Mustang.

"They were pretty rough and unfixable," she said. "But you probably couldn't convince him of that."

Bittiker's family has a history of service. His father served in the Marines and his mother worked for the Department of Defense.

"We all supported the mission there. He knew what he was doing was for a good cause and he believed in what he was doing," Wheat said.

Funeral arrangements for the four Soldiers are incomplete, the National Guard said in statement.

The 120th Combined Arms Battalion is part of North Carolina's 30th Heavy Brigade Combat team, headquartered in Clinton. The 30th consists of 4,000 soldiers, mainly from North Carolina, with additional troops from West Virginia and Colorado. The 30th mobilized at the end of last year and left North Carolina in late April. It is expected to return from the deployment in early 2010.