A car bomb near a popular restaurant killed four people and wounded 25 in northwestern Baghdad on Thursday, police said.
The explosion in the Shiite district of Shula occurred while police officers and construction workers were eating breakfast on Christmas Day.
Officials said at least two police officers were among the injured.
The Shiite-led Iraqi government had declared Thursday a national holiday to show what it said was its solidarity with other religious groups in Iraq.
Violence has dropped sharply in Iraq, where the U.S.-led invasion in 2003 unleashed years of sectarian and insurgent attacks. But car bombs, suicide bombs and assassinations are still routine.
A week ago, twin bomb blasts killed 18 people and wounded 53 in central Baghdad.
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