At least 20 people were killed and 50 others wounded when two booby-trapped car bombs were detonated late Monday near Iraq's Shiite holy city of Karbala, a local police source said.

"At least 20 pilgrims died in the blasts and more than 50 others wounded," the source told Xinhua on condition of anonymity.

The explosions occurred this evening targeting the pilgrims who headed to Karbala to participate a ceremony of Imam Mehdi's birthday.

Sporadic attacks are still common in Iraq as part of recent deterioration in security which shaped a setback to the efforts of the Iraqi government to restore normalcy in the country more than four months after the violence-torn country held parliamentary elections on March 7.

Major Shiite commemorations have often been targeted by various armed groups in Iraq. Despite tight security, attacks still happen.