The death toll from Saturday's massive bombing in Somali capital Mogadishu has risen to 276, with about 300 people injured, according to Information Minister Abdirahman Osman.

In a tweet, the minister held Al-Shabaab, the terrorist organization which began its insurgency attacks in 2007, responsible for the "barbaric attack".

The militant group, linked to Al-Qaida,has carried out several deadly attacks in the past. However, it had not yet claimed responsibility for the truck bomb killings Saturday.

DEADLIEST SINGLE ATTACK IN HISTORY

The explosion happened at the KM5 junction, a shopping area that is usually busy in the afternoons. A truck packed with explosives detonated near the entrance of the Safari Hotel, basically destroying the whole area.

It was the deadliest single attack in Somalia's history. The toll is expected to rise.

"In the 10 years that I have been working in Mogadishu as a first responder, I have not seen anything like this," a doctor at Aamin Ambulance Service told VOA News.

BBC reported that the hotel had collapsed, with people trapped under the rubble.

Hospitals appealed for blood to help save the injured.

President Mohamed Abdullahi Mohamed declared three days of mourning as the Horn of Africa country reeled under the massive explosion, calling it a "heinous act."

There were angry protests at the scene of the blast a day after.

INTERNATIONAL CONDEMNATION

The United Nations' senior envoy in Somalia on Sunday condemned the bombing and offered the world body's support.

"The international community will do everything possible to help the people and government of Somalia to overcome this tragedy," Michael Keating, the UN Secretary-General's Special Representative for Somalia, said in a statement.

Keating said the UN and the African Union Mission in Somalia were working closely to support the response by the Somali government and local government authorities in Mogadishu, including providing logistical support, medical supplies and expertise.

The United States condemns "in the strongest terms" the terrorist attacks that killed and injured innocent Somalis, a U.S. Department of State statement said.

Turkey has responded to the request by Somali leaders to send an air ambulance that will fly the injured to Turkey for treatment, Osman said in his Twitter account.

Djibouti, Kenya and Ethiopia have offered to send medical aid to assist the injured, the minister added.