An anti-terrorism protest in Mogadishu, Somalia, on Oct. 15. (Mohamed Abdiwahab/AFP via Getty Images)

After three days of mourning, thousands of men and women marched through the streets of Somalia's capital Wednesday, answering the Mogadishu mayor's call for unity in the wake of the country's deadliest terrorist attack, which occurred over the weekend.

Meanwhile, Somali intelligence officials began to divulge details of how the attackers, who killed at least 320 people, managed to get inside the heavily guarded city. Although no official account has been released, much of the information given to journalists unofficially matches up on a basic sequence of events.

In what is known as a “knock-knock” strategy, the attackers hoped to detonate a small bomb to blast open the gates of the intended target, allowing a large truck laden with explosives to enter. The intended target of the attack is unclear; different officials have offered possibilities, including government ministries, embassies, army compounds where Somali troops are being trained by Turkish, American and African allies. The bustling intersection where the truck eventually exploded is not thought to have been the intended target.

That knock-knock plan went awry when a minivan carrying the smaller bomb was stopped, and its payload found. While police attempted to dismantle the bomb, it exploded, but no one was hurt. The larger truck also attracted the suspicion of police, who stopped it at a checkpoint. The driver ultimately made it through by phoning someone whom the officers manning the checkpoint trusted.

But at a second checkpoint downtown, security personnel insisted that the truck be inspected thoroughly. According to reporting by the Voice of America, the driver panicked and sped off into one of the busiest parts of the city.

There, in the middle of an intersection packed with pedestrians, taxis, street vendors and roadside eateries, the truck detonated. A nearby tanker truck filled with petroleum ignited into a giant fireball. Many of the dead were charred beyond recognition. A prominent hotel and numerous buildings were leveled.


Government forces and civilians gather at the scene of an explosion in Mogadishu on Oct. 15. (Feisal Omar/Reuters)

Somalia's president, Mohamed Abdullahi Mohamed, blamed the attack on al-Shabab. The militant group has routinely carried out small-scale bombings in Somalia, but Saturday's attack ended a few months of relative calm. In addition to the still-growing death toll, at least 400 people were injured and dozens remain unaccounted for.

Al-Shabab has not claimed the attack, but analysts say no other group in Somalia has the capability to carry out such a sophisticated strike.

“There is detailed scholarship that suggests leaders of organizations using terror tactics are unlikely to claim responsibility for a particular attack if they anticipate negative political fallout from it,” said Paul D. Williams, a professor at George Washington University who specializes in Somalia. “The massive demonstrations by Somalis against Saturday's attack show an overwhelmingly negative view of it. Hence al-Shabab's leaders would be foolish to claim responsibility.”

Al-Shabab is the armed wing of an Islamist political organization that used to be in power but was deposed by a U.S.-backed Ethiopian invasion of Somalia in 2006. Since then, al-Shabab, which means “the youth,” has controlled ever-diminishing swaths of the country, mostly its southern regions, though it has continued to mount attacks on Mogadishu. Now, only rural areas remain under its control, and it has no established presence in any major Somali towns or cities. The group presents itself as a savior of the homeland and sees the government as a foreign-backed occupier, while also pledging allegiance to al-Qaeda, a terrorist network with global affiliates.

Al-Shabab's control of rural regions has exacerbated droughts in the past decade, because it has prevented aid groups from accessing affected areas. In 2011, more than a quarter-million people perished, and hundreds of thousands were displaced this year after consecutive seasons of failed rains. Progress against al-Shabab, mostly because of the efforts of 22,000 African Union troops aided by U.S. airstrikes, meant that aid groups had greater access this year.

The Trump administration has given the U.S. military greater powers to fight al-Shabab by designating parts of Somalia as areas of “active hostilities,” and drone strikes and raids involving U.S. troops picked up over the summer. In May, a Navy SEAL was killed in one of the raids, marking the first U.S. combat death in Somalia since 1993.

But Saturday's attack proved — as it was intended to — that al-Shabab is not on the out and out and that it is not averse to killing large numbers of civilians.

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