Baghdad  - A string of politically-targeted attacks took place on Tuesday across Iraq, as the country gears up for provincial council elections on January 31.

Unknown militants set fire to a school that was set to be a polling station in the town of Falluja, about 50 kilometres west of the Iraqi capital Baghdad, a security source said.

The school was completely destroyed, the source told Deutsche Presse-Agentur dpa, adding that security around polling stations would be tightened across the country.

In the city of Mosul, a car bomb exploded near the headquarters of the Kurdistan Democratic Party (KDP) in eastern Mosul, killing four people and injuring one, a security source told dpa.

Mosul, the capital city of Nineveh province, lies some 400 km north of Baghdad.

In Baghdad, three policemen were wounded in a blast that occurred in the centre of the city, according to security forces.

A bomb went off near Uqba Bin Nafie Square as a police patrol vehicle was passing the location, the source said.

"The dead included four Iraqi army officers," the source said, adding that a member of Kurdish militia forces, or Peshmerga, was also wounded.

In a separate incident in Mosul, Iraqi army troops captured four gunmen who belonged to al-Qaeda in Iraq group, a military source said. One of the detainees was said to be a leader of the armed group.

"They are residents of the Talafar district and one of them is wanted for perpetrating six murders in al-Karama neighbourhood in eastern Mosul," he was quoted by VOI as saying. (dpa)