At least 20 people were killed Friday when radicals attacked worshippers at a Shiite mosque in Pakistan’s troubled north-west, officials said.

The attackers struck during prayers at the mosque in the Hayatabad area of Peshawar, the capital of Khyber-Pakhtunkhwa province, provincial Information Minister Mushtaq Ghani said.

The head of Hayatabad Medical Complex, Muhammad Imran, told dpa that 20 dead and 41 injured were taken to the facility.

At least four attackers wearing suicide vests were involved in the attack, bomb disposal chief Shafqat Malik said. Three of them were said to have detonated their vests, and one was killed by security forces.

Local police official Naseebur Rehman confirmed that the attack was over and firing had stopped.

An eye-witness told broadcaster Geo TV that the attackers, wearing police uniforms, threw hand grenades and then started firing.

Taliban radicals took responsibility of the attack.

“The attack is revenge for security forces operations and the killing of Taliban,” rebel spokesman Mohammad Khurasani said.

The Taliban are Sunni radicals who often target Shiites because they see them as heretics.

Shiites make up about 20 per cent of Pakistan’s mostly Sunni population.

Last month at least 60 Shiite worshippers were killed when a suicide bomber attacked their mosque during Friday prayers in the Shikarpur area of the southern province of Sindh. SAPA