The statement said the blast also left 20 U.S. soldiers and an Iraqi civilian injured. It said 15 of the wounded soldiers were able to return to duty after receiving medical treatment.
Reports say Diyala has recently been seeing fighting involving U.S. and Iraqi forces and Sunni and Shi'ite militias.
The deaths of the soldiers raised to 85 the number of U.S. service members who have died in Iraq so far in April, making it the deadliest month for U.S. troops since December, when 112 died.
The Imam Al-Mahdi Army on parade (epa)
HAS THE CONFLICT IN IRAQ BECOME A CIVIL WAR? Many observers have concluded that the tit-for-tat sectarian violence that emerged after the February 2006 bombing of a mosque in Samarra has become a full-blown civil war.... (more)
U.S. Media Starts Using 'Civil War' Label
Iraqi Prime Minister Under Fire From All Sides
U.S. Expert Discusses Prospects For Stabilization
President Says Iraq Needs Iran's Help
Saudi Arabia To Seal Off Border With Security Fence
THE COMPLETE PICTURE: Click on the image to view RFE/RL's complete coverage of events in Iraq and that country's ongoing transition.