Abu Musab al-Zarqawi's al-Qaida linked militant group says it was behind the massacre of nearly 50 unarmed Iraqi army recruits on Saturday.
The group made the claim in an Internet posting that could not be verified.
Police say the recruits were killed -- many execution-style -- when they were returning to southern Iraq from training near Baquba. Reports say the militants were dressed as Iraqi security personnel, and some officials say the well-planned ambush of the recruits suggests militants have infiltrated Iraqi security services.
In other violence, a mortar attack near Baghdad airport killed an American diplomat and a U.S. solider. To the south, in Karbala, a car bomb killed a Bulgarian soldier.
And in Fallujah, witnesses say a U.S. airstrike on suspected insurgent positions killed six people.