Gunmen attack Iraqi church in Baghdad

"It is an armed attack on the Our Lady of Salvation church. Three explosions occurred and our forces are surrounding the area. What's really going on isn't clear to us yet," said Major General Qassim al-Moussawi, spokesman for the Baghdad operations command.

Al-Baghdadiya television station said it had received a phone call from someone claiming to be one of the attackers, who demanded the release of all Al Qaeda prisoners in Iraq and Egypt. The caller said the attackers belonged to the Islamic State of Iraq, an al Qaeda umbrella group in Iraq.

Overall, violence has fallen sharply in Iraq since the height of sectarian bloodshed in 2006-07 triggered after the 2003 U.S.-led invasion.

But attacks by Sunni Islamist insurgents linked to al Qaeda and Shi'ite militia continue on a daily basis.

The failure of Iraqi leaders to agree on a new government almost eight months after an inconclusive election has stoked tensions just as U.S. forces cut back their presence and end combat operations ahead of a full withdrawal next year.

Some police sources said two security guards were killed in Sunday's attack, which began with at least one loud explosion near the Assyrian Catholic church.