At least 28 worshippers have been killed after a suicide bomber attacked a Sunni mosque in northwest Pakistan.

According to Deputy chief of the Mohmand tribal district administration Naveed Akbar, the victims of Friday's attack include four children, aged 10 and younger, and dozens others were wounded, some critically.

A breakaway Taliban group has claimed responsibility for the bombing, saying they were targeting members of a pro-government militia. A curfew has since been imposed in the area.