Britons have been warned not to travel to an area of Burkina Faso following a terrorist attack on a hotel and cafe on Friday, which left 27 people dead.
The "appalling attack", condemned by the British Foreign Secretary Philip Hammond, targeted a hotspot popular with Westerners in the African country's capital, Ouagadougou.
Four Al-Qaeda militants were killed after Burkina Faso and French forces stormed the hotel and neighbouring cafe on Saturday, where hostages were being held by extremists. So far, 23 people have been confirmed dead.
After the seige ended on Saturday morning, Hammond said: "I utterly condemn the appalling attack in Ouagadougou last night and offer my deepest condolences to the families and loved ones of those who have been killed and injured.
"The United Kingdom stands with President (Roch Marc) Kabore and the people of Burkina Faso in the fight against terrorism.
"We advise British nationals in Burkina Faso to avoid the area where the attack took place, follow the instructions of local security authorities and monitor Foreign Office (FCO) travel advice."
The FCO warned against travelling north of the town of Boulsa, as it is near to the border with Mali.
The FCO advice states: "You should avoid the area and follow the instructions of local security authorities."
The siege began on Friday and ended on Saturday.
Three attackers - two of whom were female - were killed at the hotel and a fourth was killed when security forces cleared out a second hotel nearby.
There were 27 people, belonging to 18 nationalities, who were killed during the attack. The death toll could still rise, the country's security minister said.
The FCO states: "There could be unannounced demonstrations and strikes and the security situation may deteriorate. You should remain vigilant and stay away from large public gatherings.
"The airport and land borders may be subject to closure at short notice. Monitor local media and check with your airline for more information."
The local Al-Qaeda affiliate known as AQIM claimed responsibility online as the attack was ongoing in downtown Ouagadougou at the 147-room Splendid Hotel, according to the SITE Intelligence Group.
In a message posted in Arabic on the militants' "Muslim Africa" Telegram account, it said fighters had "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."
Military forces fought to take back the building on Saturday morning, which had been blackened by a fire during the assault.
The security forces took control of the Splendid Hotel and were searching nearby hotels to be sure no other extremists were hiding. The search continued even after security forces found and killed a fourth extremist at the Hotel Yibi, President Roch Marc Christian Kabore said.
About 33 people were wounded and 126 people were freed after the morning call to prayer signaled a new day in this West African nation, said Minister of Security and Internal Affairs Simon Compaore.
Cars and motorbikes were burned, and overturned chairs and shards of glass lay scattered near the hotel. Onlookers were kept far away from the fighting that continued into daylight.
The harrowing attack was launched by the same extremists behind a similar siege at an upscale hotel in Bamako, Mali in November that left 20 dead.
In a separate development, an Austrian doctor and his wife were kidnapped Friday night by extremists in Burkina Faso's north near its border with Mali, Abi Ouattara, security ministry spokeswoman, said Saturday.