At least 76 people have been killed by a vehicle bomb detonated during morning rush hour in Somalia's capital.

The blast took place at a checkpoint at a busy intersection in Mogadishu. More than 90 people were also injured.

No group has yet claimed responsibility for the bomb but al-Shabab militants have often carried out attacks there.

President Mohammed Abdullahi Farmaajo said its aim was to demoralise the Somali people, but that jihadists would never stop the country rebuilding.

Al-Shabab - a group of Islamist militants, allied to Al-Qaeda - has waged an insurgency for more than 10 years. It was forced out of the capital in 2011 but still controls areas of the country.

Witnesses described carnage at the scene.

"All I could see was scattered dead bodies ... amid the blast and some of them burned beyond recognition," said Sakariye Abdukadir, who was close to the blast.

"May Allah have mercy on the victims of this barbaric attack," the former internal security minister added.

At least 16 of the victims are students from Banadir University who were travelling on a bus that was struck by the vehicle bomb, AFP report.

"This was a black day," university chairman Mohamed Mohamud Hassan said, according to AFP. "It was a day when parents who have sent their children to learn were sent back the dead bodies of their children."