At least 14 people have been killed and 11 others injured in an attack by the al-Shabab militant group in a village in northern Kenya on Tuesday, a Kenyan official reportedly said. The news of the attack comes as the al Qaeda-linked militants reportedly stepped up their offensive during Islam's holy month of Ramadan.

The attack reportedly took place in Soko Mbuzi village in Mandera County near the Kenyan border with war-torn Somalia, during the early hours of Tuesday morning. Authorities sent a medical airplane to evacuate those who were critically injured in the attack to the capital Nairobi, according to the Kenya Red Cross. According to local reports, most of the victims were quarry workers.

"People were sleeping when the attack happened, they just came and hurled explosives in the houses," Mandera County Commissioner Alex Ole Nkoyo said, according to Agence France-Presse. "These were Al-Shabab from the nature of the attack. They used explosives and guns."

The attackers reportedly were believed to have escaped when police arrived at the scene.

Last month, al-Shabab threatened to attack "non-believers" in Kenya during Ramadan. Kenya has been under attack by al-Shabab since 2011, after Kenyan troops entered Somalia to fight the terrorist group.

In the last eight months, at least 85 people -- all of them non-Muslims -- have been killed by al-Shabab militants in Mandera County, including from an attack in December 2014 that killed 36 non-Muslim quarry workers.

In the group's deadliest attack, 148 people, mostly students, were killed by four gunmen at a university in the Kenyan town of Garissa in early April.