People clean the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)

At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said.

The suicide bomber entered the Al Zahraa mosque in Kirkuk, some 250 km north of the Iraqi capital of Baghdad, and then blew himself up, the police sources told Xinhua on condition of anonymity.

The explosion also caused damage to the mosque, the sources said, adding that the attack took place as the mosque was holding a funeral for a person who killed in an attack on Wednesday.

Earlier on Thursday, a series of car bombs and a gunfire attacked the Shiite neighborhoods in Baghdad and the northern city of Mosul, leaving at least 11 people dead and some 45 others wounded.

Violence is still common in Iraq despite the dramatic decrease since its peak in 2006 and 2007 when the country was engulfed in sectarian killings.

People gather at the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)

People clean the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)

People clean the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)

People gather at the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)

People clean the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)

People clean the blast site at a Shiite mosque in Kirkuk, northern Iraq, May 16, 2013. At least 12 people were killed and 25 others injured as a suicide bomber blew himself up at a Shiite mosque in northern Iraq's Kirkuk on Thursday, local police sources said. (Xinhua/Dena Assad)