BAGHDAD, Oct. 20 (Xinhua) -- Up to 10 worshippers were killed and some 31 others wounded on Monday in a suicide bomb attack at a Shiite mosque in the Iraqi capital of Baghdad, an Interior Ministry source said.

The attack occurred during the noon prayers when a suicide bomber detonated an explosive vest inside al-Khairat Shiite mosque at a commercial district in downtown Baghdad, the source told Xinhua on condition of anonymity.

"The latest reports said that 10 people were killed and 31 wounded in the suicide bombing in the Shiite mosque," the source said.

Earlier, the source put the toll at four killed and 12 wounded in the blast.

The attack apparently is part of series of deadly attacks during the past few days that targeted the predominantly Shiite districts in Baghdad, killing and wounding dozens of Iraqis.

Iraq has been witnessing some of the worst violence in years. Terrorism and violence have killed 5,576 civilians in Iraq in the first half of this year, with 11,666 more wounded, according to a recent UN report.