Several gunmen seized a luxury hotel in Mali’s capital on Friday, killing at least 21 people, among them an American, in an attack that raised fresh concerns about security in a country that has battled Islamist insurgents for years.

Even after a multinational campaign to defeat them, militants have proved capable of targeting prominent locations like the city’s Radisson Blu Hotel, where the seven-hour standoff took place.

Security forces swept through the Radisson on Friday afternoon, freeing the last hostages and pursuing the gunmen, who had charged through the hotel yelling “Allahu Akbar.” As the troops cleared the hotel, they found the floors littered with the bodies of Malians and foreign visitors, including a Belgian government official.

The Washington Post reports that the US State Department said a U.S. citizen was among the dead. A department spokesman had reported earlier that no Americans were killed or injured in the attack.

The incident is the latest in a year of deadly Islamist-led attacks across sub-Saharan Africa, where a patchwork of conflicts has sometimes been overshadowed by Islamic State violence in other parts of the world. From al-Shabab in Somalia to Boko Haram in Nigeria, the continent is host to a flurry of violent extremist groups, with a range of local and transnational goals, seeking to execute large-scale attacks against civilians.

In Mali, Friday’s attack underscored how vulnerable the West African country remains, even after French forces and a small number of U.S. troops helped unseat Islamists from their northern stronghold in 2013. Before that campaign, militants appeared to be gaining ground, moving closer to the capital, seizing on the chaos caused by a 2012 military coup. The current government still has only tenuous influence in parts of the country, and the remaining French forces in particular are considered targets.

The gunmen stormed the hotel early Friday, sending some of the 170 guest and staff members fleeing in panic and others cowering in hiding places. One witness said the attackers freed some captives who were able to recite verses from the Koran. By late Friday afternoon, Mali’s security minister, Col. Salif Traore, said the remaining hostages were safe.

At least 20 people were killed, Traore said. The Reuters news agency, citing U.N. officials, said at least 27 bodies were seen. Authorities worked through the evening to identify the dead.

Three U.N. staff members in the hotel during the attack were safely evacuated, said Stéphane Dujarric, spokesman for U.N. Secretary General Ban Ki-moon. U.N. peacekeepers helped secure the perimeter, provide medical aid and help in forensics, Dujarric said.

The United Nations has envoys in Bamako as part of Mali’s reconciliation efforts — what has become the deadliest peacekeeping mission of the past three years, with 53 U.N. peacekeepers killed since 2013.

Meanwhile, security forces tried to pin down the attackers in the heart of Bamako, which serves as a logistical hub for French forces aiding in the fight against Islamist militants in Mali, a nation that stretches from tropical West Africa to desert regions bordering Algeria.

A group affiliated with al-Qaeda, al-Mourabitoun, said its followers were behind the attack — similar to a smaller assault on a hotel in August that was claimed by the same group. Mali has faced repeated attacks from insurgents linked to al-Qaeda and other factions, but the Islamic State does not have major footholds in the region.

One Senegalese guest, Aissatou Gueye, was in her room when the attackers entered. Like many other guests, she was there to attend a large mining conference.

“They were asking people to recite the Koran, and if they do, nothing will happen to them,” she said outside the hotel. Gueye saw one person shot dead before she ran to safety.

About a dozen Americans were rescued from the hotel, including several employees of the U.S. Embassy in Bamako, said State Department spokesman John Kirby.

The American victim was identified by her family as Anita Datar, an international development worker from Takoma Park, Md. The U.S. ambassador to Mali called the family late Friday afternoon to inform them, Datar’s mother said. Datar, the mother of a young son, worked for Palladium, an international development firm with offices in Washington.

A member of a U.S. Special Operations unit helped to escort guests evacuated from the hotel, the Pentagon said. About 22 U.S. Defense Department personnel were in Bamako when the hotel was attacked.

Authorities drew no direct links to last week’s terrorist attacks in Paris. But Mali — home to the famous ancient city of Timbuktu — has been at the center of a French-backed effort to drive back Islamist rebels who once controlled large portions the country.

Security had been reinforced in Bamako — specifically around locations popular with foreigners, including the Radisson — after the Paris attacks, Traore said. He added that the attackers entered the hotel through a side entrance, “which makes us believe that they were familiar with the hotel.”

Foreigners are often targeted in Mali. Yet militants had never seized a target as prominent as the 190-room Radisson Blu, where foreign businessmen and diplomats are known to stay and dine.

Earlier this month — before the rampage in Paris — the leader of Ansar Dine, one of Mali’s main Islamist groups, released a statement encouraging attacks that would “push away the aggression of the French Crusader assailant” in the former French colony.

A contingent of French troops is stationed in Mali, and President François Hollande on Thursday had praised the campaign against the Islamist insurgents.

“France is leading this war with its armed forced, its soldiers, its courage,” he said. “It must carry out this war with its allies, its partners giving us all the means available, as we did in Mali, as we are going to continue in Iraq, as we will continue in Syria.”

One of the rescued hostages, popular Guinean singer Sékouba “Bambino” Diabate, told reporters that he hid under his bed and heard two assailants speaking in English as they searched an adjacent room.

“I stayed still, hidden under the bed, not making a noise,” he said. “I heard them say in English: ‘Did you load it? Let’s go.’ ”