MOGADISHU, Somalia (AP) -- Al-Qaida-linked militants launched their deadliest single bomb attack ever in Somalia on Tuesday, killing at least 70 people and demonstrating how the group that blocked aid to famine victims can still mount devastating violence even after most of its fighters fled the capital in August.
A truck loaded with drums of fuel exploded outside the Ministry of Education, where students accompanied by their parents registered for scholarships offered by the Turkish government. The thunderous blast covered the city in dust more than a half-mile away, leaving blackened corpses sprawled on the debris-strewn street amid burning vehicles. One woman used a blue plastic bucket to pour water on a smoldering body.
Even in a city mired in war and anarchy for two decades, Tuesday's attack by the al-Shabab group horrified rescue workers. Ali Abdullahi, a nurse at the city's Medina Hospital, said countless victims were being brought in with amputated limbs and burns.
"It is the most awful tragedy I have ever seen," he said. "Imagine dozens are being brought here minute by minute. Most of the wounded people are unconscious and others have their faces blackened by smoke and heat."
Duniya Salad sobbed over her brother's burnt body after he died while undergoing treatment at the hospital.
"They killed him before he started university! Why was he killed? Damn to al-Shabab," she said.
Al-Shabab, which was formed about five years ago, immediately claimed responsibility for the attack on a website it uses.
"Our Mujahideen fighters have entered a place where ministers and AMISOM foreigners stay," al-Shabab said in a brief post on a website, referring to the Ugandan and Burundian forces who make up the African Union peacekeeping mission.
The attack took place on one of the busiest streets in the capital, and it was not clear whether the Ministry of Education was the intended target.
Two years ago, al-Shabab was blamed for a devastating attack on a graduation ceremony that killed 24 people, including three government ministers, medical students and doctors.
U.N. Secretary-General Ban Ki-moon said he is "appalled" by the "incomprehensible" attack, which came as local leaders are trying "to chart a peaceful political future for Somalia."
The secretary general of the Organization of the Islamic Cooperation, Prof. Ekmeleddin Ihsanoglu, condemned what he called a "heinous" attack on civilians.
Ali Muse, the chief of Mogadishu's ambulance service, told The Associated Press that at least 70 people had been killed Tuesday and at least 42 others were wounded.
"The explosion has not only affected the targeted place, but even passer-by people and car passengers died there. The death toll may increase and we are still carrying many dead bodies," he said. "It is the worst tragedy I have ever seen in the capital."
In a statement, the government gave a death toll of 15. It was not immediately clear if it was an early count.
"The casualties are mostly students and parents who were waiting for results of scholarships from the Ministry of Higher Education," the government said. "The attack shows that the danger from terrorists is not yet over and that there are obviously still people who want to derail the advances that the Somali people have made toward peace."
The deadliest attack comes as Somalia struggles to rebound from its worst famine in 60 years, a crisis that has brought even more misery to this country that descended into anarchy and war in 1991.
Al-Shabab fighters have compounded the suffering by preventing aid agencies from helping famine victims in areas under militant control in southern Somalia. The U.S. says 29,000 children have died since the famine began, and the U.N. says 750,000 more are at risk of starving to death in the next several months.
Witnesses say the insurgents even killed men who tried to flee famine areas with their families, saying it was better for them to die than accept help from the West.
Al-Shabab withdrew most of its gunmen in August amid an offensive by African Union forces.
The U.N. Special Representative for Somalia, Augustine Mahiga, had earlier warned that the al-Shabab would resort to guerrilla-style attacks following their withdrawal. "Although the extremists have left the capital, it is very difficult to prevent these types of terrorist attacks which we have consistently warned are likely to be on the increase," Mahiga said.
Suicide bombings were unheard of in Somalia before 2007, but have become increasingly frequent. Al-Shabab claims allegiance to al-Qaida, which often uses car bombs and appears bent on gaining a greater foothold in the Horn of Africa.
Al-Shabab includes militant veterans of the Afghanistan and Iraq conflicts who have trained Somalis in tactics like suicide bombs and sniper fire, and until recently hosted the most wanted al-Qaida operative in Africa. Fazul Abdullah Mohammed, al-Qaida's top operative in East Africa, was killed by a Somali government soldier at a security checkpoint in the capital in June.
Mohammed was the mastermind behind the 1998 bombings of U.S. embassies in Kenya and Tanzania.
Al-Shabab carried out a double suicide bombing in Uganda in July 2010 that killed 76 people watching the World Cup final on TV. Americans of Somali heritage also have joined the group