The protesters, consisting mostly of young men and women, marched through Mogadishu wearing red headbands and chanting slogans like "down with the enemy… down al-Shabaab."
"We are demonstrating against the terrorists that massacred our people," Halima Abdullahi, who lost six relatives in the attack, told the Guardian.
The protesters eventually gathered at the city's Banadir soccer stadium, where they were joined by the Somali President Mohamed Abdullahi Mohamed and other leaders.
Following the deadly attack, the country's president implored Somalis to unite in the fight against the violent Islamist group al-Shabaab, a group linked to al-Qaeda, claiming that the militant group's "fingerprints" could be found on Saturday's attack. Al-Shabaab has a history of committing similar attacks.
"It is time for us to unite and I call for all Somalis to join hands together in the fight against the common enemy," the president said, VOA news reported.
"I call for the politicians who have relationships with foreign countries to put our differences aside and join us in the fight against the militants," he added.
Mogadishu Mayor Taabit Abdi Mohamed also added that "[the] Somali people must be ready for a war to liberate this city."
The protesters eventually marched from the stadium to the blast's location and held a memorial ceremony for the victims.
In pursuit of its radical Islamic vision, al-Shabaab has bombed dozens of targets in Mogadishu and massacred hundreds of people in brutal terrorist attacks since its insurgency began in 2007. The terrorist group has not yet claimed responsibility for the deadliest attack in Somalia's history.