Unknown gunmen attacked a convoy of vehicles carrying Shiite pilgrims in northern Iraq on Tuesday, killing three pilgrims and wounding 10 others, a source from local U.S. and Iraqi liaison office said.

"Gunmen ambushed the convoy of Shiite pilgrims between Himrin mountain and the Udaim dam east of Tikrit City, 170 km north of Baghdad," a source from the Joint Coordination Center of Tikrit told Xinhua on condition of anonymity.

An official of the Iraqi parliament, who is a brother of Mohammad Mahdi al-Baiyati, a Shiite lawmaker, was among the pilgrims heading from the northern city of Kirkuk to the holy Shiite city of Karbala, some 110 km southwest of Baghdad, the source said.

Baiyati's brother escaped unhurt, but three pilgrims were killed and 10 others wounded in the attack, the source added.

Bodyguards escorting the convoy traded fire with the gunmen, the source said, adding that one of the attackers was killed while the others fled the scene.

Baiyati's family and his brother live in the ethnically mixed Kirkuk City. He is a member of the Badr Organization, the armed wing of the Supreme Council for the Islamic Revolution in Iraq ( SCIRI), a Shiite political party with close ties to Iran.

Earlier on Monday, a spate of roadside bombs and car bombs in Baghdad killed and wounded dozens of Shiite pilgrims, who were heading to the holy city of Karbala to commemorate the occasion of Arba'een (40 days after the day of Ashura).

It is the commemoration of the martyrdom by beheading of Imam al-Hussien bin Ali, the grandson of Prophet Muhammad, who was killed in the 17th century.

Source: Xinhua