A suicide bomber on a motorbike attacked a police patrol as it passed through an Iraqi market tonight, leaving 38 people dead or injured.
The attack came in the centre of Muqdadiyah, 100km northeast of Baghdad, at nightfall.
At least 24 people had been killed earlier and 83 injured in a suicide truck bombing at a police station in the northern Iraqi city of Baiji.
Police said the bomber struck the front gates of the police directorate in the city, 180km north of Baghdad.
The new headquarters had just been opened in the past few days, after an identical attack on the original station in June killed 27 people, including 13 policemen.
Elsewhere, 14 US soldiers were killed when their helicopter crashed in northern Iraq this morning.
The US military said in a statement that initial indications suggested that the Black Hawk helicopter had suffered mechanical failure.
The crash was the worst since January 2005, when 31 US personnel were killed when a Marine transport helicopter was downed.
Bush frustration
Meanwhile, US President George W Bush has expressed frustration with Iraqi leaders, saying the government in Baghdad needs to do more to combat extremism.
Mr Bush's comments came a day after a leading Democratic Senator, Carl Levin, urged Iraq's Assembly to replace the government led by Prime Minister Nuri al-Maliki.
Mr Levin called for a less sectarian administration.
However, Mr Bush said it was up to the Iraqi people and not the US to decide whether to replace Mr Maliki and other leading politicians.
On a visit to Syria, Mr Maliki rejected US criticism of his government, saying no one has the responsibility to set a timetable for the Iraqi government.
