The bombing occurred near a police check post just yards away from where a remote-controlled bomb hit a police van, killing four policemen and a child, less than an hour earlier.

The woman, said to be 25 years old, was wearing an explosive-laden vest and blew herself up in the heart of the main northwestern city of Peshawar.

"She exploded the vest as she came close to the check post. One policeman was wounded," police official Tariq Omar told Reuters.

He said a 60-year-old woman was also killed in the suicide bombing and police were investigating whether she was an accomplice or a passer-by.

Fourteen people were wounded in the earlier attack on the police van. The bomb, concealed in a push-cart, exploded as the van passed by.

Reuters