Soldiers of France and United States attend rescue campaign in Burkina Faso's capital Ouagadougou, Jan 16, 2015. [Photo/Xinhua]

OUAGADOUGOU - Security forces in Burkina Faso retook a hotel in the capital on Saturday a day after al-Qaida fighters seized it in an assault that killed at least 28 people from at least 18 countries and marked a major escalation of Islamist militancy in West Africa.

Until Friday's attack, the landlocked nation in the arid reaches of the southern Sahara, had largely been spared the violence that has plagued its neighbours.

The assault follows a similar raid in November on a luxury hotel in Mali's capital Bamako which killed 20 people, including citizens of Russia, China and the United States.

The Ouagadougou assault, claimed by al-Qaida in the Islamic Maghreb (AQIM), marked an expansion of operations for Islamist militants who are stepping up their activities, echoing the growth of Islamic State in the Middle East.

President Roch Marc Christian Kabore said 28 people were killed in the 146-room Splendid Hotel, in the Cappuccino restaurant across the street and at a second nearby hotel, the Hotel Yibi, according to an initial death toll.

In this image taken from local television, a rescued woman sits in a vehicle with bullet hole in windshield near the Splendid Hotel, Jan 15, 2016, in Ouagadougou, Burkina Faso. [Photo/CFP]

Speaking on state-run television, Kabore said 156 hostages had been freed by the security operation to retake the area, while around 50 civilians had been wounded. Four members of the security forces, including one French soldier were also wounded.

"Faced with these terrorists and their vile acts, we must mobilise to ensure the appropriate response to put them out of action," Kabore said.

"We will emerge victorious from this war, which has been imposed upon our people and all other people of the world who want peace and freedom," he said, adding that the nation would observe three days of mourning from Sunday.

Authorities had earlier said that victims of 18 different nationalities were killed in the attack which targeted an area popular with Westerners and French soldiers based in Burkina Faso.

Burkina officials gave no further details of the victims, but the French government announced on Saturday that two French citizens were among the dead. Paris pledged to send forensic experts to help investigate the attack, and a French court opened an investigation for murder and attempted murder.

Six Canadians died in the assault, Prime Minister Justin Trudeau said. Switzerland lost two citizens and the Netherlands one, the two nations' foreign ministries announced.