A suicide bomber killed five U.S. soldiers in northern Iraq, in the single largest loss of American life in Iraq in more than a year.
Two Iraqi policeman were also killed in the blast in Mosul Friday. Iraqi officials said at least 65 other people were injured, including members of U.S. and Iraqi security forces.
The U.S. military said a suicide bomber set off an explosive-laden truck outside a police base in Mosul. Witnesses say the truck barreled through a nearby police checkpoint, prompting Iraqi forces to open fire.
Officials said the target was the base, not the U.S. patrol that happened to be nearby.
The military added that two people suspected of involvement in the bombing in Mosul have been detained.
Violence remains common in Mosul, as extremists exploit divisions between the city's Arabs, Kurds and other ethnic and religious groups.
U.S. forces are set to withdraw from Iraqi cities by the end of June.
In an interview with the Times of London published Thursday, the U.S. Commander in Iraq, Ray Odierno, said troops may need to stay in Mosul beyond the deadline.
Other parts of Iraq have experienced a sharp reduction in violence in the past year, but a series of bombings in Baghdad in recent days has claimed dozens of lives.