The most powerful bomb blast ever witnessed in Somalia’s capital has killed more than 300 people, making it the deadliest single attack in this Horn of Africa nation.

“We have confirmed 300 people died in the blast. The death toll will still be higher because some people are still missing,” Abdikadir Abdirahman, the director of Amin ambulances, said.

In a tweet, Information Minister Abdirahman Osman called the attack “barbaric” and said countries including Turkey and Kenya had already offered to send medical aid.

Hospitals were overwhelmed a day after a truck bomb targeted a crowded street near key government ministries, including foreign affairs.

As angry protesters gathered near the scene of the attack, Somalia’s government blamed the al-Qaeda-linked al-Shabab extremist group for what it called a “national disaster.” However, Africa’s deadliest Islamic extremist group, which often targets high-profile areas of the capital, is yet to comment.

Al-Shabab earlier this year vowed to step up attacks after both the Trump administration and Somalia’s recently elected president announced new military efforts against the group.

The Mogadishu bombing is one of the deadliest attacks in sub-Saharan Africa, larger than the Garissa University attack in Kenya in 2015 and the US Embassy bombings in Kenya and Tanzania in 1998.

Doctors at Mogadishu hospitals struggled to assist badly wounded victims, many burned beyond recognition. “This is really horrendous, unlike any other time in the past,” said Dr Mohamed Yusuf, the director of Medina hospital.

“Nearly all of the wounded victims have serious wounds,” said nurse Samir Abdi. “Unspeakable horrors.”

The country’s Somali-American leader, President Mohamed Abdullahi Mohamed, has declared three days of mourning and joined thousands of people who responded to a desperate plea by hospitals to donate blood.

“They don’t care about the lives of Somali people, mothers, fathers and children,” Prime Minister Hassan Ali Khaire said of the attackers. “They have targeted the most populated area in Mogadishu, killing only civilians.”

The United Nations special envoy to Somalia has called the attack “revolting”, saying an unprecedented number of civilians had been killed.