The siege at a luxury hotel in Nairobi that left 14 people dead has ended after militants who launched an attack on the complex were “eliminated”, Kenya’s president said.

Gunmen stormed the DusitD2 hotel during a suspected terror attack in the Westlands district of the city on Tuesday afternoon, setting off explosions and shooting people.

The Foreign Office has announced a British citizen is among the dead. An American man is so far thought to be the only other foreign national known to have died.

The British national killed in an attack in Nairobi has been named as Luke Potter by his employer, the international development charity Gatsby.

Mr Potter had been the organisation’s Africa programmes director for the past 10 years.

“We are deeply shocked and saddened to confirm that Luke Potter, our Africa programmes director, was killed in the recent security incident in Nairobi,” the charity said in a statement.

“Luke had devoted the past ten years of his career to helping some of the poorest and most vulnerable people in the world. He had worked with us for three and a half years, carrying out assignments across East Africa.”

Special forces had been sent to flush out the insurgents holed up inside the building, with officials announcing the area had been secured several hours later.

The Islamist militant group al-Shabaab has said its fighters were responsible for the attack.

Kenyan leader Uhuru Kenyatta said on Wednesday morning the security operation at the complex was over and all “terrorists” involved had been killed.

“The security operation at dusit complex is over, and all the terrorists eliminated,” he said. “As of this moment, we can confirm that 14 innocent lives were lost through the hands of these murderous terrorists.”

The president did not say Wednesday how many attackers were involved in the incident, but urged Kenyans to “go back to work without fear”.

Mr Kenyatta announced 14 civilians had been killed, contradicting earlier reports the death toll stood at 15, while more than 700 others had been safely evacuated during the attack.

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At least two groups of people had remained trapped inside the hotel complex early on Wednesday, with gunfire still ringing out at the scene.

Kenya’s national police chief, Joseph Boinnet, said the coordinated attack on the hotel began with an explosion in a car park outside a bank followed by a suicide bomber inside the hotel lobby.

Streams of people were initially seen running from the complex, some injured. Others were trapped inside buildings, forced to wait several hours for medical treatment or evacuation.

Nairobi hotel attack – in pictures Show all 23 1 /23 Nairobi hotel attack – in pictures Nairobi hotel attack – in pictures Cars are seen on fire at the scene where explosions and gunshots were heard at the Dusit hotel compound, in Nairobi, Kenya Reuters Nairobi hotel attack – in pictures An injured man is evacuated from the scene of an explosion at a hotel complex in Nairobi's Westlands suburb AFP/Getty Nairobi hotel attack – in pictures A soldier takes cover next to a bullet ridden window EPA Nairobi hotel attack – in pictures People run for cover during gunfire and explosions in Nairobi EPA Nairobi hotel attack – in pictures Kenyan security forces take position following an explosion at a hotel complex in Nairobi's Westlands suburb AFP/Getty Nairobi hotel attack – in pictures Security forces on the scene of an explosion in Nairobi AP Nairobi hotel attack – in pictures Cars burn at the scene of an explosion in Nairobi AP Nairobi hotel attack – in pictures People are led away from the scene of an explosion at a hotel complex in Nairobi AFP/Getty Nairobi hotel attack – in pictures A soldier takes cover as gunfire continues at the scene of a suspected terror attack in Nairobi EPA Nairobi hotel attack – in pictures Armed plain clothes officials secure the damaged entrance of a hotel during ongoing gunfire and explosions in Nairobi EPA Nairobi hotel attack – in pictures Members of security forces take cover at the scene Reuters Nairobi hotel attack – in pictures People are evacuated from the scene of a suspected terror attack in Nairobi Reuters Nairobi hotel attack – in pictures Cars burn after an explosion in Nairobi AP Nairobi hotel attack – in pictures A member of security forces holds a weapon at the scene Reuters Nairobi hotel attack – in pictures Security forces advance at the scene of a suspected terror attack in Nairobi Reuters Nairobi hotel attack – in pictures Cars burn at the scene of an explosion in Nairobi Reuters Nairobi hotel attack – in pictures A glass damaged by bullets at the scene Reuters Nairobi hotel attack – in pictures Security personnel on the scene of a suspected terror attack in Nairobi Reuters Nairobi hotel attack – in pictures A woman is helped at the scene of an explosion in Nairobi Reuters Nairobi hotel attack – in pictures Security forces advance at the scene of a suspected terror attack in Nairobi Reuters Nairobi hotel attack – in pictures Security personnel on the scene of a suspected terror attack in Nairobi Reuters Nairobi hotel attack – in pictures Undercover police are on the scene of a blast in Nairobi AP Nairobi hotel attack – in pictures Security personnel on the scene of a suspected terror attack in Nairobi AP

CCTV footage circulated in local media purported to show at least four gunmen entering to complex. Witnesses described seeing armed men dressed in green clothing draped in bandoliers of bullets.

Many of those killed are thought to have been sitting at a restaurant in the complex when the gunfire broke out.

Enoch Kibet, who works as a cleaner for the business, said she escaped by crawling out of a gate in the basement of the building after hearing an explosion.

Nairobi attack witness says attackers were 'not normal people' and had 'black bullets' attached to them

“We were changing our shifts and that is when I heard a loud blast and people were screaming,” she said. “I couldn't believe I was alive. The blast was so loud and shook the whole complex.”

Militants from al-Shabaab, a Somalia-based group aligned to al-Qaeda, asserted the attack had killed 47 people in a release through its news agency, but gave no further details.

The organisation is also thought to have been behind the siege on the Westgate shopping mall, around a mile from the DusitD2 complex, which killed 67 people across several days in 2013.