Baghdad  - Four US soldiers and four Iraqis were killed on Monday, while 21 were injured in separate attacks in Baghdad, Mosul and Diyala provinces, raising fears for security in Iraq's January 31 provincial elections.

The four US soldiers died when two helicopters crashed in northern Iraq.

"Four coalition forces members were killed when two aircraft went down in Salah al-Din governorate, in northern Iraq, at approximately 2:15 am (2315 GMT)," US army spokesman al-Meqdad Jebrael told Voices of Iraq (VOI) news agency.

The cause of the crashes is unknown and is under investigation, Jebrael added.

The accident put the number of US soldiers killed in Iraq to 15 this month and brought the total number of US soldiers killed since the invasion began in early 2003 to 4,236.

In western Baghdad, 10 Iraqi policemen were wounded when a bomb exploded near their vehicle, according to a police source.

The source told VOI that a roadside improvised explosive device went off in the Mansour neighbourhood of Baghdad while a police patrol vehicle was passing by.

In downtown Baquba, six civilians were wounded in a bomb blast, local media reported.

The blast took place as a motorbike bomb went off near a joint checkpoint set up by police and Awakening councils forces in the Tahrir area of Diyala, a spokesman for Diyala's police department told VOI.

In Mosul, two were killed and five injured, including a policeman in separate attacks. One of the attacks included a car rigged with explosives detonated near a police checkpoint in al-Dawasa, downtown Mosul, VOI reported.

Meanwhile, police are looking for gunmen who fatally shot an Iraqi civilian in the al-Wehda neighbourhood of Mosul and fled the scene.

In another incident, unknown gunmen killed a civil servant working for the Independent High Electoral Commission (IHEC) in the Yarmouk neighbourhood in the eastern part of Mosul.

The IHEC is a nine-member panel charged with overseeing balloting in the January 31 provincial elections.

The incident is the latest attack against candidates and elections personnel in different parts in Iraq ahead of the elections.

In Hillah, an independent candidate running for the municipal elections in Iraq escaped an assassination attempt when unknown gunmen opened fire on his house on Saturday.

That assassination attempt came a week after gunmen killed Haitham al-Lihaibi, a candidate for the Babil provincial council from Prime Minister Nour al-Maliki's list. dpa