In the deadliest attack of Somalia's long civil war, more than 300 people have been killed and hundreds injured by a devastating truck bomb that destroyed buildings and vehicles on a busy downtown street in Mogadishu.
Hospitals were overwhelmed by the dead and wounded. They pleaded for blood donations as the toll escalated from the Saturday blast. Many of the victims were burned beyond recognition and may never be identified.
There was no immediate claim of responsibility, but the attack was widely believed to be the work of al-Shabab, a militant Islamist group with links to al-Qaeda that has battled for control of Somalia for a decade. Analysts said the group might not be claiming the attack immediately because the shocking death toll had caused such outrage in the country.
A large Western-funded peacekeeping force of more than 20,000 African troops has been fighting the radical militia for years, and the United States has been ratcheting up its own military involvement this year, including drone strikes and special forces operations, but the rebels have continued to mount attacks on targets across the country. They have even gained territory in recent months in some parts of the country.
The latest attack, in which the assailants managed to bring a large truck through several checkpoints to reach the centre of the city, showed that the insurgents remain well-organized and capable of striking almost anywhere.
Hundreds of angry demonstrators marched through the streets of Mogadishu on Sunday in a protest against al-Shabab.
Somalia President Mohamed Abdullahi Mohamed declared three days of national mourning for the victims. He was among hundreds of people, including politicians and foreign diplomats, who crowded into hospitals to donate blood for the injured.
"It is now clear that without adequate and appropriate support to Somalia, many of the security gains made in recent years could be reversed," said the chair of the African Union commission, Moussa Faki Mahamat, in a statement condemning the attack.
He appealed to the international community to "ensure a more co-ordinated and robust international support to Somalia's institutions in their struggle to defeat terrorist groups."
Top commanders of the Pentagon's Africa command visited Mogadishu earlier this year to meet Somalia's president and discuss ways to fight al-Shabab.
In May, a U.S. special forces soldier was killed and two others were wounded while assisting Somali soldiers in a clash with al-Shabab about 65 kilometres west of Mogadishu. It was the first U.S. combat death in Somalia since the famous "Black Hawk Down" battle of 1993.
After the massive explosion on Saturday, the government of Turkey was the first to respond, flying a plane into Mogadishu with medical aid. Officials planned to airlift some of the injured to Turkey for medical treatment.
Among those killed in the blast were five volunteers from the Somali Red Crescent Society, a charitable aid group. Several others from the same group were injured. "The number of casualties may rise as some volunteers are still missing," the group said.
The director of humanitarian affairs in Somalia's government, Mohamoud Elmi, was also killed in the blast. "He was one of the hardest-working members of our team," said Dr. Maryan Qasim, the minister of humanitarian affairs and disaster management, in a tweet on Sunday.
Another victim was a 22-year-old woman named Maryan Abdullahi, who was due to graduate as a medical doctor on Sunday after years of study.
In Ottawa, the Global Affairs Department said it was not aware of any Canadians affected by the explosion. It said it condemned the "horrific" attack and was monitoring it closely.
With a report from Daniel Leblanc
Geoffrey York