An al Qaeda-linked group has said it was behind the early morning attack in Mali's capital, Bamako.
The gunmen targeted a military training school and other areas of the city, officials said. The army in its statement termed the attackers as 'terrorists'.
After residents heard gunshots on Tuesday, the army said attackers had struck near the city's airport but the situation was now “under control”.
Jamaat Nusratul Islam wal Muslimeen (JNIM) – the group that claimed responsibility for the attack – has been waging a militant Islamist insurgency in Mali for more than a decade, among other groups.
JNIM is considered one of the most active militant groups in the wider Sahel region, having carried out numerous attacks in Mali, Burkina Faso and Niger.
It said its “special operation” hit both the training center and Bamako's military airport on Tuesday, causing heavy human and material losses.
The army did not mention any such casualties, but said “a group of terrorists tried to infiltrate the Faladi Gendarmerie School in the morning”.
The security ministry said the school was one of several “sensitive locations” that were “targeted by terrorist attacks” in the early hours.
Two members of the security forces told news agency AFP that they were wounded in the attack.
In the afternoon, Mali's state television channel broadcast footage showing about 20 prisoners. All the men were blindfolded and their wrists were bound.
“The terrorists have been neutralized. The sweep is on,” Army Chief of Staff Umar Diara said during an ORTM news report.
However, he did not mention the attack on the military airport, which the JNIM claimed to have targeted.
The news report also showed footage of three motionless bodies lying on the ground.
The Ministry of Security had earlier assured residents that they could continue their activities as normal after the attack. In contrast, international organizations such as the United Nations have reportedly advised their staff to limit their movements.
Videos posted on social media earlier showed black clouds of smoke rising from a part of the city.
Reuters reported that people going to the mosque for morning prayers had to turn back as the gunfire started.
Bamako's Modibo Keita International Airport has been closed following the attack.
The military seized power in a coup in 2021, accusing the government of failing to do enough to quell the coup.
The army has pulled out French troops and UN peacekeepers and brought in Russia's Wagner Group to help fight the jihadists, but the insurgency shows no signs of abating.