A bomb blast killed seven people at a Shiite Muslim mosque in eastern Baghdad on Friday and wounded more than 20, police sources said.
The explosion took place in the Baladiyat neighborhood. A senior police source said that either a suicide belt or improvised explosive device had been used in the attack, for which there was no immediate claim of responsibility.
The source said the death toll was expected to rise with many of those wounded in serious condition.
It was a rare attack on a Shiite place of worship in the Iraqi capital.
Baghdad's security improved significantly with the defeat of Daesh in 2017 and bomb attacks of any kind in the city have been rare since then.
Turkey strongly condemned the attack.
"It was sadly learned that people have been killed and injured, as a result of a suicide bomb attack at a mosque in the Baladiyat district of Baghdad," said a statement by the Turkish Foreign Ministry.
"We strongly condemn this terrorist attack against civilians in a sacred space. We convey our condolences to the friendly and brotherly people of Iraq," it added.
The statement also stressed that Turkey will continue to support Iraq's fight against terrorism.