A powerful bomb went off outside the shrine of a Sunni Muslim saint in northwestern Pakistan on Sunday, killing at least four people, police said.

Senior police officer Mumtaz Khan said 23 people were also wounded in the attack at the shrine of Kaka Sahib in the town of Nowshehra. Hundreds of devotees were present there at the time, and the dead and injured had been transported to a hospital.

There was no claim of responsibility but Pakistani militants such as the Taliban have been blamed for previous such attacks.

The militants follow a strict version of Islam and they claim visiting shrines is not allowed.

Nowshehra lies 50 kilometers (30 miles) east of Peshawar, the capital of Khyber Pakhtunkhwa province that borders Afghanistan. It is also believed to a hiding place for Taliban insurgents, who often target security forces and government officials to force Islamabad to stop backing Washington in the war against terrorism.