Scene of a massacre after at least 20 people are killed by a suicide bomber inside a Sunni mosque in central Iraq.

The attack took place in the middle of a sermon.

It is unclear who was behind the blast -- the latest in a campaign of attacks that has raised fears of a return to full-blown sectarian conflict in a country where Kurds, Shi'ite and Sunni Muslims have yet to find a stable way of sharing power.

The grief comes as more than 460 people have been killed in militant attacks in July alone -- according to the monitoring group Iraq Body Count.