Colonel Abdel-Karim al-Jubouri, Mosul's police chief, said the attack took place at a checkpoint at around 8.45am local time (0545 GMT) in Tal Afar, about 420 kilometres northwest of Baghdad.

 

The attacker ploughed a truck laden with explosives into the wall of a house used as a lookout by soldiers in the Al-Salam district of the town, the AFP news agency reported.

 

Four soldiers and 10 civilians were killed in the attack, while at least 13 more people were wounded, police said.

 

Eyewitnesses told Aljazeera that ambulances transferred the army's casualties to a nearby military base for treatment.

 

In March, George Bush, the US president, praised Tal Afar as an example of the progress being made in Iraq after US-led forces drove out al-Qaeda fighters in a 2005 offensive there.

 

Last month, at least 17 people died after a suicide bomber blew himself up in the town.

 

Meanwhile, at least two people died and four more were injured when a mortar shell hit a house in the early hours of Saturday morning in Iskandariyah, 50km south of the Iraqi capital of Baghdad, police said.

 

More than 50,000 Iraqi and US troops are currently deployed around Baghdad in support of Operation Together Forward, an attempt to quash a wave of bloody sectarian violence in the country. 

 

Security crackdown

 

Meanwhile on Saturday, thousands of Iraqi police and soldiers launched a major security crackdown in the restive Iraqi oil city of Kirkuk, searching homes for weapons after all residents were ordered off the streets.

 

Kirkuk, 250 km north of Baghdad, is an ethnically mixed city claimed by Arabs, Kurds and Turkmen which has seen an upsurge of violence.

 

Major-general Shirko Shakir, Kirkuk's police chief, said that cars and pedestrians had been cleared from the city's streets after an indefinite curfew was imposed on Friday night.

 

He said: "This operation is an attempt to control the deterioration of the security situation in the city. We will continue until we clean up the city and end insurgent activity."

 

Major-general Jamal Taher said that a 15 km trench had been dug south of the city in the last week to try to prevent fighters and car bombs from entering the city.