Burkina Faso troops supported by French special forces were battling Al-Qaeda linked gunmen in the early hours of Saturday in a Ouagadougou hotel where at least 20 people have been killed.

Sixty-three hostages were rescued, 33 of them wounded, from the Burkinabe capital's four-star Splendid hotel about two hours after the assault began and heavy gun battles were still being waged on the top floors of the hotel, popular with UN staff and foreigners.

Twenty people have been confirmed dead, but the toll could rise further as interior minister Simon Campaore told AFP that firefighters had seen 10 bodies on the terrace of a restaurant opposite the hotel.

It was not clear how many people remained trapped.

"We don't yet have a total tally of the dead. The Burkinabe forces are still combing the hotel," Campaore told AFP

He said it was unclear how many attackers were still inside the 147-room hotel.

"The assault is ongoing with the Burkinabe forces supported by French special forces," communication minister Remis Dandjinou told AFP.

The attack comes less than two months after a jihadist hostage siege at the luxury Radisson Blu hotel in the Malian capital Bamako left 20 people dead, including 14 foreigners -- an attack claimed by the same Al-Qaeda affiliate behind the unfolding Ouagadougou assault.


'Revenge against France'

A fire raged at the main entrance of the hotel and screams could be heard from inside, while on the street outside about 10 vehicles were set alight.

The head of the city's main hospital confirmed prior to the start of the counter-assault at least 20 people had been killed and another 15 injured.

A restaurant opposite the hotel was also attacked and a staff member, reached by telephone, said several people had been killed, but was not able to give an exact toll.

Al-Qaeda in the Islamic Maghreb (AQIM) claimed responsibility for the attack saying it was "revenge against France and the disbelieving West", according to US-based monitoring group SITE.

The "mujahideen brothers" of AQIM "broke into a restaurant of one of the biggest hotels in the capital of Burkina Faso, and are now entrenched and the clashes are continuing with the enemies of the religion", SITE quoted the group as saying.

The attackers were members of the Al-Murabitoun group based in Mali and run by Mokhtar Belmokhtar, SITE said.

An AFP reporter at one point saw three men clad in turbans firing at the scene on Avenue Kwame Nkrumah, one of Ouagadougou's main thoroughfares.

A witness also reported seeing four assailants who were of Arab or white appearance and "wearing turbans".

- Unprecedented attack -

The French embassy said on its website that a "terrorist attack" was underway and urged people to avoid the area. An Air France flight from Paris to Ouagadougou was diverted to neighbouring Niger.

A US defence official, speaking on condition of anonymity, said Washington could provide drone-based surveillance.

The Burkinabe army, meanwhile, said a heavily-armed group of about 20 people had also carried out an attack on Friday near the border with Mali, killing two people -- a gendarme and a civilian -- and leaving two others wounded.

Several attacks have taken place in Burkina Faso in recent months, but no such assaults had hit the capital.

In April the Romanian security chief of a mine in northern Tambao was kidnapped in a move also claimed by Belmokhtar's Al-Murabitoun group.

Burkina Faso is part of the G5 Sahel grouping that counts the fight against terrorism as part of its remit.

It has also offered support to France's Barkhane counter-terror mission, spanning five countries in Africa's restive Sahel region, and French special forces are stationed in Ouagadougou's suburbs.

Last month, Burkina Faso swore in Roch Marc Christian Kabore as president, completing the troubled West African state's transition after the overthrow of its longtime ruler Blaise Compaore in 2014 and a failed coup attempt in September.