President Uhuru Kenyatta had earlier announced the end of a 20-hour operation at the DusitD2 complex which saw hundreds of people rescued and all five jihadists “eliminated”.
The bloody assault was claimed by the Al-Qaeda-linked Somali militant group Al-Shabaab, which said it was acting to avenge the decision by US President Donald Trump to declare Jerusalem as Israel’s capital, according to the SITE monitoring group.
Chilling CCTV footage broadcast on local media showed four black-clad, heavily armed men calmly entering the luxury complex on Tuesday afternoon.
A suicide bomb blast signalled the start of the attack.
Police chief Joseph Boinnet revised the death toll to 21 from 14, saying the victims included 16 Kenyans, one American, one Briton and three of African descent.
“Six other bodies were found at the scene and one police officer succumbed very suddenly to his injuries,” he told reporters.
Another 28 wounded people had been admitted to hospital, he said.
As police searched for further victims, bomb disposal experts were looking for any grenades left by the assailants.
“The public must not panic if it hears explosions from the area,” Boinnet said.
As the first explosion and gunfire rang out in the leafy Westlands suburb on Tuesday, hundreds of terrified office workers barricaded themselves in the complex while others fled.
At least one suicide bomber blew himself up and others traded gunfire with security forces as the assault on DusitD2, a complex which includes a 101-room hotel, spa, restaurant and offices, unfolded.
“There were five terrorists and all of them are no more,” Boinnet told AFP earlier. “It is a clearing exercise now going on there.” Al-Shabaab has targeted Kenya since it sent its army into Somalia in October 2011 to fight the jihadist group.
Among the dead was an American citizen, identified by his family as Jason Spindler, whose brother said on Facebook that he had been a survivor of the September 11, 2001, attacks in the United States.
In London, the Foreign Office confirmed the death of a British-South African dual national and said another British person was injured.
In downtown Nairobi, dozens of people lined up to give blood at a memorial for the US embassy destroyed in an Al-Qaeda attack in 1998 in which 213 people died.
For many Kenyans, news of the attack revived traumatic memories of a 2013 Shabaab raid on Nairobi’s Westgate shopping mall that left 67 people 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.
George Kinoti, the director of criminal investigations, told AFP that “two principal suspects” had been arrested.
One was arrested in the suburb of Eastleigh and the other in Ruaka, northwest of Nairobi, where officers raided a house where one of the attackers lived, he said.
“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.
A police source said two attackers were shot dead Wednesday 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.”
Distraught family members gathered outside a mortuary, 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.
Francis Magutu, 35, said he had been at the morgue since 6 am. “I am almost certain that my in-law is dead, but I want us to see his body, because we want to be certain.”
The attack sparked a wave of outrage abroad, from UN Secretary General Antonio Guterres and African Union chief Moussa Faki to the European Union.
At home, 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,” the editorial said. (Agencies)