Seven workers at a factory making building supplies in Sorkhord district in the eastern province of Nangarhar were killed in an attack by unknown armed men on Wednesday night, the provincial police chief Major General Juma Gul Himmat said on Thursday.

Sources said the victims were employed at the factory and were residents of Bamiyan.

The police chief said that four suspects have been arrested in connection with the incident.

Photos from the incident show that the victims’ had been shot to death and their hands had been bound.

The motive behind the attack is unknown so far.

No group has claimed responsibility.