Smoke rises from the blast area after an attack at an upmarket hotel and office complex in Nairobi (Picture: PA).
Somalia-based extremist group al-Shabab has claimed responsibility for an attack on a luxury hotel complex in Kenya's capital of Nairobi.
Witnesses and police at the scene in the city called it the latest terror attack in a country that has seen a number of deadly incidents in recent years.
The British Army has a permanent training unit in Kenya, BATUK.
Most troops are based in Nanyuki, 200km north of Nairobi, but a small number are based in the capital as well.
So far, there has been no request from the Kenyan Government for assistance.
The complex in Nairobi's Westlands neighbourhood includes a large hotel.
"We are aware that armed criminals are holing up in the hotel, and special forces are now currently flushing them out," said Kenya's national police chief, Joseph Boinnet.
A Kenyan police officer said bodies were seen in restaurants downstairs and in offices upstairs, but "there was no time to count the dead".
As night fell, gunfire continued more than two hours after the first shots were heard at the complex.
A bomb disposal unit was on the scene and vehicles were being cordoned off for fear that they contained explosives.
An unexploded grenade was seen in a hallway of the complex.
A witness said he saw five bodies at the entrance. He said that other people were shouting for help and "when we rushed back to try to rescue them, gunshots started coming from upstairs, and we had to duck because they were targeting us and we could see two guys shooting".
Kenyan hospitals appealed for blood donations even as the number of wounded remained unclear.
The attack has reminded many Kenyans of the Westgate Mall attack in Nairobi in 2013, when al-Shabab extremists burst into the luxury shopping centre, hurling grenades and starting a day-long siege that left 67 people dead.
During that attack, former British Army Major Dominic Troulan helped save 200 lives, returning to the Mall 12 times to search for and rescue people.