Iraqi police have raised the death toll from an ambush in Diyala province to 35 people, most of whom were police officers.
Gunmen ambushed the group of Iraqi policemen and anti-al-Qaida fighters on Wednesday.
Meanwhile, the U.S. military said Thursday a suicide bomber killed an American soldier Wednesday in Diyala.
In other news, Iraqi lawmakers on Wednesday passed a bill that calls for provincial elections to be held by January 31, several months later than originally planned.
U.S. President George Bush and U.N. Secretary-General Ban Ki-moon praised the move, saying it will contribute to political reconciliation in Iraq.
The measure was adopted after Iraqi lawmakers agreed to postpone voting in the oil-rich region of Kirkuk and the three autonomous Kurdish provinces of northern Iraq.
Kirkuk has been the focus of a power-sharing dispute among the city's ethnic Kurds, Arabs and other minorities. Iraqi lawmakers accepted a U.N. proposal for a multi-ethnic committee to review the Kirkuk dispute and prepare for local elections there by March.
Before the bill becomes law, it must be approved by Iraq's three-member presidential panel, which includes a Shi'ite Arab, Sunni Arab and Kurd. Iraqi Kurdish lawmakers' support of the bill makes it more likely to be accepted by the panel than a previous measure.
Washington has been pressing Iraqi leaders to take advantage of a drop in violence to four-year lows to boost reconciliation efforts.
Some information for this report was provided by AFP, AP and Reuters.