Fort Riley ? Army officials on Thursday announced the names of five soldiers from Fort Riley’s 1st Infantry Division who were killed this week in Iraq.

The attack on Monday was one of the deadliest days for soldiers assigned to Fort Riley since the war in Iraq began in 2003.

1st Infantry Division officials said the men were killed when insurgents attacked their base. The soldiers were assigned to the 1st Battalion, 7th Field Artillery Regiment.

Killed were Spc. Emilio Campo, 20, a combat medic from Madelia, Minn.; Pfc. Michael Cook, 27, a field artillery data systems operator from Middletown, Ohio; Pfc. Christopher Fishbeck, 24, a field artillery data systems operator from Victorville, Calif.; Spc. Robert Hartwick, 20, a combat medic from Rockbridge, Ohio; and Pfc. Michael Olivieri, 26, a field artillery data systems operator from Chicago.

“We are deeply saddened by the loss of these young heroes and our thoughts and prayers go out to their families,” said Lt. Col. Andrew Gainey, the soldiers’ battalion commander. “They were all outstanding soldiers, outstanding people and most importantly, our good friends.”

The soldiers deployed to Iraq in November 2010. They were part of the 2nd Advise and Assist Brigade, supporting the development of Iraq forces and the improvement of civilian life in central Iraq.

Each of the soldiers had served less than two years and each was on his first deployment.

U.S. Sen. Jerry Moran, a Kansas Republican, noted that the soldiers died on the 67th anniversary of the D-Day landings in France in 1944. During that invasion, soldiers from the 1st Infantry Division were among the first to wade ashore.

“These brave young men answered the call to serve our country, and Americans are forever indebted to them for their service and sacrifice,” Moran said in a statement.

The deaths were among the highest single-day casualty totals for Fort Riley soldiers since the wars in Iraq and Afghanistan began.

Five soldiers of the 1st Battalion, 1st Engineer Battalion were killed on March 31, 2004, when a bomb exploded under their M-113 armored personnel carrier in Malahma, an area in the Sunni Triangle.

More than 18,000 soldiers are assigned to Fort Riley, located about 60 miles west of Topeka.