Iraqi officials say a car bomb has exploded in central Baghdad, killing at least 18 people and wounding 50.

The Monday morning blast in the Baab al-Muadham neighborhood damaged an office for Shi'ite religious affairs that manages religious and cultural sites.

The explosion follows a series of attacks that killed 17 people in Baghdad last week.

The spike in attacks coincides with a ratcheting-up of months-long political tensions in which several political parties have called for Prime Minister Nouri al-Maliki to be unseated.

Violence in Iraq has declined dramatically since its peak in 2006 and 2007, but attacks remain common.