Somalia has declared three days of mourning after an explosion on Saturday in Somalia’s capital, Moqadishu, which killed at least 85 people.

The blast, which occurred at a busy junction, also wounded 250 people, an official from the city's ambulance service said.

Following the attack, President Mohamed Abdullahi Mohamed Farmaajo declared three days of national mourning starting on Sunday.

“We will observe three days of mourning for innocent victims, flags will be flown at half-mast. Time to unite and pray together. Terror won't win,” President Mohamed said in a statement published on Twitter.

Moqadishu’s residents have described the blast as the most powerful they had witnessed in the city in years.

“I call on our citizens to come out, extend help, donate blood and comfort the bereaved. Let's get through this together,” Mohamed said.

No group has yet claimed responsibility for the incident.

Nearby homes and businesses flattened and vehicles turned into burned wrecks as a result of the explosion.

The city’s mayor urged residents to donate blood as hospitals were running out of blood.

"I call on the Somali people to visit the city's hospitals and donate blood. Please, come to the rescue of your brothers," Thabit Abdi Mohammed said after donating blood at a local hospital.