Indiana Adjutant General Martin Umbarger said the four members of the Valparaiso-based 713th Engineer Company died Thursday morning in southern Afghanistan. He said all of the men were combat engineers who specialized in clearing major supply routes.

The blast occurred as their vehicle traveled along a road, scouting for signs of roadside bombs and other potential problems convoys might encounter as the move supplies in the decade-long war in Afghanistan, Umbarger said.

"Their mission is to keep the major supply routes clear of all obstacles for the convoys. And what that means is they're the first ones to go out to make sure the route can be used, so it's a very important mission — but it's also extremely dangerous," he told The Associated Press.

The four men killed were identified as: Staff Sgt. Jonathan M. Metzger, 32, of Indianapolis, Spc. Brian J. Leonhardt, 21, of Merrillville, Ind., Spc. Robert J. Tauteris Jr., 44, of Hamlet, Ind., and Spc. Christopher A. Patterson, 20, of Aurora, Ill.

A fifth soldier injured in the blast, Pvt. Douglas Rachowicz, 29, of Hammond, Ind., was initially treated at a military base hospital in Kandahar before being airlifted to the U.S. military hospital in Landstuhl, Germany, Umbarger said.

Tauteris' uncle, Ed Tauteris of North Judson, Ind., said the family has been devastated by the death.

He said his nephew, who grew up in rural northwestern Indiana's Starke County and graduated from North Judson High School, was a loving, attentive father to his two sons, Robert Tauteris III and Matthew.

"He was great father who loved his kids, took very good care of them. He was a great provider. He'd work seven days a week, come home and take his kids fishing, hunting, to baseball, stuff like that," he said.

Ed Tauteris, 69, said his nephew reenlisted in the National Guard after his 21-year-old son, Robert III joined up and was sent to Afghanistan. He said his nephew had hoped he might be able to keep his son safe during his deployment.

He said Robert Tauteris III, who was still in Afghanistan when his father was killed, accompanied his father's body back to the U.S.

"He flew home with his dad. That poor kid. I feel so bad for him," he said.

Umbarger said the four soldiers' deaths were the greatest number of Indiana guards since March 2005, when four members of the Indianapolis-based 76th Infantry Brigade died when a land mine exploded under their military vehicle about 30 miles south of the Afghan capital of Kabul.

Gov. Mitch Daniels said in a statement that Umbarger called him Saturday morning to tell him of the deaths. The governor said he's praying for the soldiers' families.

" I received from the adjutant general the news a person in my job dreads the most, that we have lost soldiers in combat. I had begun to hope that I had received the last such phone call, and cannot convey the sadness which it instantly brought," Daniels said.

"My prayers are joined with those of millions of Hoosiers who will hear this terrible news with deep grief but also with gratitude for the courage of those we have lost, and pride that we come from a state that produces men such as these," he said.

Umbarger said the four soldiers' families were informed Friday of the deaths, and the last family members were told the news Friday night. He said he's "humbled and honored" by the courage of the nation's service members and said the sacrifices of the four men won't be forgotten.