Attackers struck an upscale hotel popular with westerners in Burkina Faso's capital late Friday. Three hours later, gunfire could still be heard as soldiers in an armoured vehicle finally approached the area.

An Associated Press reporter near the scene in the West African country said that several cars were also ablaze outside the 147-room Splendid Hotel in downtown Ouagadougou.

Robert Sangare, director of Ouagadougou's university hospital, said about 20 people have been killed and 15 wounded.

Minister of Communications Remis Dandjinou said on Saturday that 33 hostages, including one government minister, were freed from the hotel.

However, Dandjinou said on Twitter, "the operation continues."

A U.S. official, who spoke on condition of anonymity, said France had requested immediate U.S. intelligence, surveillance and reconnaissance support to help retake the hotel in its former colony.

splendid hotel burkina faso

Witness Vital Nounagnon told the reporter he saw four men attack the hotel and neighbouring Cappuccino Cafe about 7:30 p.m. Another witness who gave only his first name, Gilbert, said that when security forces first arrived, they turned around rather than confront the attackers.

"But we know that the gunmen won't get out of the hotel alive," he said. "Our country is not for jihadists or terrorists. They got it wrong."

The reporter saw an armoured vehicle with security forces arrive nearly three hours after the attack.

Al-Qaeda has taken responsibility for the attack, according to the SITE Intelligence Group.

The U.S. Embassy in Ouagadougou tweeted: "We are closely following the situation downtown."

While Burkina Faso has largely been spared the violence racked by Islamic extremist groups in Mali, a Romanian national was abducted last April.

Burkina Faso, a largely Muslim country, has been in turmoil since its longtime president was ousted in a popular uprising in late 2014. Last September members of a presidential guard launched a coup that lasted only about a week. The transitional government returned to power until Burkina Faso's November election ushered in new leaders.

Curfew imposed on capital

A curfew had been put in place in Ouagadougou from 11 p.m. GMT to 6 a.m. the next morning, France's ambassador to the country said on Saturday.

Gilles Thibault said on his Twitter account the attack in France's former colony was continuing and that the embassy had set up a crisis unit for its citizens. More than 3,500 French nationals live in the country, according to foreign ministry data.

With files from Reuters