Nine people have been arrested in Kenya following an attack on a luxury hotel compound in the capital Nairobi that killed at least 21 people.

All five militants who stormed the DusitD2 hotel and business complex on Tuesday have been killed, officials say, and a major hunt is under way to find those who helped organise it.

Somalia-based Islamist group al-Shabab says it was behind the attack.

Kenya's Red Cross says everyone who was missing has now been accounted for.

What do we know about the attackers?

Kenyan media reports that the wife of one of the suspected attackers has been arrested in Kiambu county, just north of Nairobi.

Police said they had identified Ali Salim Gichunge, also known as Farouk, through the car used in the attack.

Police stand guard outside the home of one of the suspected attackers, in Kiambu County

Neighbours told The Standard newspaper that he and his wife had moved in to their home in October. The couple were secretive, they said, and had put the contents of their home up for sale before the attack, saying they were "moving out of Nairobi this week".

President Uhuru Kenyatta said on Tuesday that five jihadis carried out the attack, and all were "eliminated" by security forces after a 19-hour siege.

Al-Shabab issued a statement calling the attack "a response" to US President Donald Trump's controversial decision to recognise Jerusalem as the capital of Israel.

A White House National Security Council spokesman responded by saying: "This senseless act is a stark reminder of why the United States remains resolved in our fight to defeat radical Islamist terrorism."