A suicide bomber posing as a shepherd blew himself up near a Shia mosque in Kabul on Friday killing at least six people, police said, as Muslims prepare to observe the holy month of Muharram

The attack in the north of the Afghan capital happened as worshipers were gathered inside Hussainia mosque, one of the biggest Shia centers in the city, for Friday prayers.

“A suicide bomber who was grazing sheep has detonated himself outside” the mosque, General Salim Almas, criminal investigative director of Kabul city, told AFP.

Six people were killed and 16 wounded, Kabul deputy police chief Sadeq Muradi told AFP, but the health ministry put the death toll at two and 10 wounded.

Kabul's Emergency hospital tweeted that it had received 19 wounded including four children.

There was no immediate claim of responsibility but fighters belonging to the Taliban and the militant Islamic State (IS) group have repeatedly targeted the minority Shia community in recent years.

A shopkeeper told AFP that the suicide bomber blew himself to bits after he was identified by suspicious civilian guards who had set up a checkpoint about 200 meters from the mosque.

Afghanistan has trained and armed more than 400 civilians to help protect Shia mosques during the holy month.

The attacker had apparently wanted to reach the mosque while worshippers were still inside the prayer hall. Salim Shaheen, who had been inside the mosque at the time of the blast told AFP there were multiple casualties.

“We were busy offering our Friday prayers when a big bang happened and we stopped prayers and rushed out,” Shaheen told AFP.

Shaheen said “several people were killed and wounded”. He and other bystanders took 15 people including six children to hospital.

There had been fears insurgents would strike again as Shias prepare to commemorate Ashura which falls this weekend.