The Al Shabab group has killed 36 non-Muslim quarry workers after singling them out near the north Kenyan town of Mandera.
The attack took place early on Tuesday. Witnesses said that the victims were caught by the militants after midnight while they were sleeping in their tents at the quarry in Kormey, 15 km from Mandera, reported the BBC.
A driver who visited the scene of the attack, Ali Sheikh Yusuf, said that most of the victims seemed to have been lined up and shot in the head at close range.
The group had earlier shot 28 non-Muslim passengers on a bus in northern Kenya after separating them from Muslims by asking them to read from the Koran.
The incidents have raised concerns over security in the regions bordering Somalia.
The militant group claimed responsibility for the attack on quarry workers and blamed the involvement of Kenyan forces in Somalia and their ongoing atrocities against Muslims.
Kenya's Red Cross said that its security personnel and one of its teams were on the ground at the site of the attack.
Al Shabab has stepped up its campaign in Kenya after the nation sent its forces across the border to help battle the militants.
