MOGADISHU, SOMALIA -- An explosives-laden vehicle detonated Saturday at a security checkpoint in the central Somalia city of Beledweyne, killing at least 15 people and wounding 40 others, authorities said.

Abdifatah Mohamed Yusuf, the director-general of the Hirshabelle Ministry of Humanitarian and Disaster Management, confirmed the deaths.

"Twenty of the wounded have been admitted to Beledweyne hospitals, while another 20 are in critical condition, prompting a request for their airlift to Mogadishu for advanced medical treatment," he said.

Hirshabelle is a state that includes Beledweyne, which is the capital of the Hiran region and has been the centre of the Somali government's latest military offensive against extremists from East Africa's al Qaeda affiliate, al-Shabab.

Images on social media showed black smoke billowing and a smashed truck cab blazing at the checkpoint.

Dr. Suleyman Abdi Ali, the director of Beledweyne General Hospital, said the bodies of 10 victims were brought to his hospital.

There was no immediate claim of responsibility from al-Shabab, which often carries out such attacks and controls parts of Somalia.