A car bomb exploded near a sacred Shi'ite shrine in the southern Iraqi city of Najaf on Thursday, killing at least 15 people, police said.

March 28, 2006 file photo of the Imam Ali mosque in the holy Iraqi city of Najaf March 28, 2006. A car bomb exploded near a sacred Shi'ite shrine in the southern Iraqi city of Najaf on Thursday, killing at least five people, police said. A Reuters correspondent said he saw 10 bodies and body parts on the ground a few hundred meters from the Imam Ali shrine, which is sacred to Shiites around the world. [Reuters]

A Reuters correspondent said he saw 10 bodies and body parts on the ground a few hundred meters (yards) from the Imam Ali shrine, which is sacred to Shi'ites around the world.

The blast came at a highly sensitive time when Iraqi leaders are struggling to form a government four months after parliamentary elections, raising fears that the deepening political vacuum will fuel sectarian violence.

Pressure is mounting on Prime Minister Ibrahim al-Jaafari to step down and break a deadlock over the new government.

But he refuses to heed calls by Sunni Arab and Kurdish rivals and even senior members of his own Shi'ite alliance to withdraw his nomination for the next cabinet.

The crisis has exposed deep divisions among Iraq's ruling Shi'ites, who dominate the government and are backed by militias who have clashed in cities such as Najaf.