A suicide bomber has killed at least 19 people at a Shia mosque in central Baghdad, officials have said, while violence elsewhere in Iraq left four dead, the latest in a protracted surge in bloodshed.

The bomber blew himself up at the entrance to the mosque in Baghdad's Shorja district on Tuesday as worshippers were preparing for midday prayers.

Another 26 people were wounded in the blast, security and medical officials said.

Elsewhere in the capital, roadside bombs in the Sadr City and Dura districts left two people dead.

Bombings in the main northern city of Mosul killed another two people.

The attacks came as Iraq's Shia-led government struggles to contain the worst surge in sectarian violence since the country was pushed to the brink of civil war in 2006 and 2007.

The UN says violence killed 8,868 people last year.

Violence has surged in the past year to its highest level since 2008, while anti-government fighters control the city of Fallujah, a short drive west of Baghdad and parts of another.

Al Jazeera