In the first incident, the guardsmen died when two roadside bombs exploded minutes apart targeting two patrols in northern Iraq on Wednesday morning, an Iraqi official said.

"A roadside bomb exploded at 7.45 am (0445 GMT) in the path of a national guard patrol in Tuz (60km north of Kirkuk)," said national guard general, Anwar Muhammad. Two of the guardsmen were wounded.

Also on Wednesday, violent clashes erupted between tens of armed men and Iraqi and US forces on the highway near al-Dura area south of Baghdad, Aljazeera has learned.

Civilians have been injured as a result of the clashes and several civilian cars left burning.

It is still unclear whether both sides suffered casualties.

In Mosul, armed men attacked a police station in the al-Zuhur neighbourhood on Wednesday, killing three policemen and injuring four including a senior officer, Aljazeera has learned.

In a separate incident, unknown attackers set alight two Turkish oil tankers in the city.  

Tikrit fighting 

In Tikrit on Tuesday night, five Iraqi civilians were killed and 20 wounded in fierce fighting which erupted between Iraqi security forces and armed fighters, police said.

A roadside blast in Balad has
left one US soldier dead

Colonel Ismail al-Jiburi said the fighting broke out in a busy shopping area in the centre of Baiji, 180km north of the capital.

Two lorries, three cars and one house were set ablaze. Iraqi security forces imposed a curfew on Baiji and set up checkpoints around the town centre.

It was not clear how the clashes began.

A convoy of trucks protected by US forces came under attack from fighters on a road further south, police said.

Two lorries were set ablaze in the attack near the village of Ishaqi and their Iraqi drivers killed.

Karbala attack

Also on Tuesday night, armed assailants attacked a police station in the city of Karbala on Tuesday night, killing one policeman and wounding five, the US military said.

Two car bombs detonated near the police station in Karbala, 110km southwest of the capital. Fighters then attacked it with mortars and machine guns, the US military said in a statement on Wednesday.
 
Armed men stormed three police stations in the eastern city of Baquba on Tuesday and another in southwestern Baghdad.

At least 50 were killed in weekend attacks on police in western Iraqi towns and the city of Samarra. 
  
Elsewhere, a roadside bomb killed a US soldier and wounded another near the Iraqi town of Balad, north of Baghdad on Wednesday, the US military said.

It said the bomb struck a 1st Infantry Division combat patrol at about 4.20am (0120 GMT) near the town, 80km from the Iraqi capital.