(AFP) - Kenyan President Uhuru Kenyatta said Wednesday that gunmen who stormed a luxury hotel complex, killing 14 people, had been "eliminated" after an almost 20-hour operation in which hundreds of civilians were rescued.

The attack was claimed by the Al-Qaeda-linked Somali group Al-Shabaab, which has targeted Kenya since it sent its army into Somalia in October 2011 to fight the jihadist group.

At least one suicide bomber blew himself up and others swapped gunfire with security forces as the assault on DusitD2, a complex which includes a 101-room hotel, spa, restaurant and offices, unfolded on Tuesday.

"There were five terrorists and all of them are no more," Kenyan police chief Joseph Boinnet told AFP. "It is a clearing exercise now going on there."

For many Kenyans, news of the attack revived traumatic memories of a 2013 Shabaab raid on Nairobi's Westgate shopping mall that left 67 dead -- a siege played out over four days that led to sharp criticism of the authorities' response.

But this time, local media heaped praise on the security forces for their intervention, which Kenyatta said entailed the evacuation of some 700 civilians.

"I can confirm that... the security operation at Dusit complex is over and all the terrorists eliminated," Kenyatta said in a televised address to the nation.

"As of this moment, we have confirmation that 14 innocent lives were lost to the... terrorists, with others injured."

- Two arrested -

George Kinoti, the director of criminal investigations, told AFP that "two principal suspects" had been arrested in connection with the attack.

He said one was arrested in the suburb of Eastleigh, and the other in Ruaka, northwest of Nairobi, where officers carried out a raid on a house where one of the attackers lived.

"One of the men was identified by locals, who called police and they have confirmed that he lived there with his wife," a police source said on condition of anonymity.

CCTV footage broadcast on local media showed four black-clad, heavily-armed men entering the complex on Tuesday afternoon.

At least one of them blew himself up at the start of the attack.

A police source said two attackers were shot dead Wednesday morning after a prolonged shootout.

"The two have red bandanas tied around their forehead and bullets strapped around their chest with several magazines each," the senior police officer said.

"Each had an AK47 which has been secured."

- Briton, American among dead -

The attack began at about 3pm (1200 GMT) on Tuesday, with a loud blast followed by gunfire and rapid calls for help spreading on Twitter.

Boinnet earlier said the attack began with an explosion targeting three cars in the parking lot and a suicide bombing in the hotel foyer.

Police sources and a mortuary official had previously reported 15 dead.

Among the dead was an American citizen, a State Department official said.

The British foreign office confirmed the death of a British-South African dual national and said another British person was injured.

A mortuary official said there were also 11 Kenyan victims, one with no papers, as well as an unidentified torso of a male adult.

It was a tormented night for families of those trapped as they waited outside the hotel while sporadic gunfire rang out.

After dawn, explosions and shooting intensified until the complex was secured mid-morning.

In downtown Nairobi, dozens of people lined up at a memorial for the US Embassy destroyed during an Al-Qaeda attack in 1998 to give blood.

- 'Very confident' attackers -

As the first explosion and gunfire rang out in the leafy Westlands suburb, hundreds of terrified office workers barricaded themselves in the complex while others fled.

Distraught family members arrived at a nearby mortuary on Wednesday, where they said they had not been permitted to view the bodies.

"My sister is not in any of the hospitals and the last time we spoke she was a bit calm but suddenly she started crying and shouting and I could hear gunshots and her phone remained on but she wasn't speaking," said a woman who gave her name as Njoki.

"We have no doubt her body is here. Let them allow us in", she said, weeping.

One survivor rescued from the building told a local television station the attackers were "very confident; they were people who knew what they were doing".

John Maingi said there had been "a flash of lights and a loud bang" at the Secret Garden restaurant where he works.

"When I peeped outside I saw a human leg which has been cut off. We hid in the room and then some police officers rescued us," he said.

- 'Chilling reality' -

An editorial in the Daily Nation newspaper said the attack was a stark reminder that Kenya's security challenges were far from over.

The last major attack in the country took place in 2015, when Shabaab killed 148 people at the university in Garissa, eastern Kenya.

Since then sporadic attacks have targeted security forces mostly in the remote northeastern parts of the country.

"Just when we thought that things were calm, the gangs unleashed mayhem. For Kenyans the chilling reality is that the attacks are not ceasing," read the editorial.

© Agence France-Presse