Three British nationals are among the victims in an attack in a shopping mall in Nairobi, Kenya, the British Foreign Office said on Sunday.

On the incident at the Westgate Centre in Nairobi, Kenya, and with reports of both assailants and civilians still in the building, a Foreign Office spokesperson said that three British nationals are confirmed dead.

The next of kin of those nationals have been informed. The number of British nationals confirmed as killed is likely to rise as further information becomes available, the spokesperson said.

The British government's crisis committee met again earlier on Sunday, chaired by Foreign Secretary William Hague. Britain has sent a rapid deployment team from London to Nairobi to provide further consular support.

A group of Al-Shabaab suspects launched an attack on the Westgate shopping mall in Nairobi on Saturday, killing at least 59 people and wounding 175 others. Nearly 50 people are still unaccounted for as 10 to 15 gunmen are still holding hostages in the building in tense standoff with Kenyan security forces.