The attacks underscore the threat to Iraq's minority Christian community following the church massacre last week that left 58 people dead. Al Qaeda militants claimed responsibility for that attack, and threatened more violence against the country's Christians.
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Police said bombs went off near four houses belonging to Christians in the Iraqi capital's predominantly Christian districts, police said. The officials said the bombs detonated within minutes of each other early Wednesday.
Police said four people were killed. Hospital officials confirmed the death toll.
It was not immediately clear whether the dead were Christians.
All officials spoke on condition of anonymity because they were not authorized to speak to the media.
The blasts come after a similar series of bombings late Tuesday that hit three empty houses belonging to Christians in western Baghdad, police officials said. No one was wounded in those bombings.
Meanwhile, Iraq's political leaders are preparing to meet for the third day in a row over the formation of a new government eight months after an inconclusive elections.
Many believe militants are exploiting the political vacuum created by the politicians' prolonged bickering over who should be the next prime minister.