A bomb attack in the centre of a market in northern Iraq has killed at least nine people and injured 13 others, including women and children, police said.

The explosion, set off by a suspected female suicide bomber, occurred on Monday morning in al-Mafraq market in Baquba, the capital of Diyala province.

Three other attacks in the same province left four more people dead on Monday, police said.

A roadside bombing in northern Baquba's al-Rahima district killed a woman, police said.

A second woman was killed by a stray bullet after locals fired guns into the air.

Over the past year, Diyala has suffered several suicide bomb attacks carried out by women, some of them causing high casualties.

The US military says al-Qaeda in Iraq is increasingly using female suicide bombers to avoid detection by security forces.

The military also says there have been more than 20 female suicide bombings this year in Iraq.