SIX British nationals have been killed in the terror attack on a shopping mall in Kenya, David Cameron said last night.

A public health consultant who was due to take up a post at the Liverpool School of Tropical Medicine (LSTM) is among the victims.

Thick smoke poured from the besieged Nairobi mall last night where Kenyan officials said their forces were closing in on Islamists holding hostages on the third day since Somalia's al Shabaab launched the raid that has killed at least 62 people.

It remained unclear how many gunmen and hostages were still cornered in the Westgate shopping centre, after a series of loud explosions and gunfire were followed by black smoke billowing from one part of the complex.

Last night the Kenya Defence Forces (KDF) reported that three terrorists have been killed and 11 Kenyan soldiers injured in the operation.

The KDF said more than 200 people have been rescued so far. Some 65 are receiving treatment in hospital.

Officials said more than 10 individuals have been arrested for questioning in relation to the attack and fire-fighters have contained the fire at the mall.

Officials said the gunmen were from "all over the world" and al Shabaab's Twitter feed suggested one of the men was Ahmed Naseer Shirdoon, 24, from London.

One of the victims, Ross Langdon had British-Australian citizenship. Mr Langdon's company, Regional Associates, said he died alongside his pregnant partner, Elif Yavuz.

Devastated relatives confirmed Zahira Bawa, 41, and her nine-year-old daughter Jenah from Leamington Spa, Warwickshire, were gunned down in the attack.

Louis Bawa flew out to Kenya when he was unable to contact his wife after news of the atrocity broke. The marketing worker was forced to wait outside the Westgate mall to receive news of Zahira and Jenah's fate.

It was reported he found the pair had died after police asked him to ID photos of dead bodies found within the shopping complex.

In a heartbreaking TV interview outside the centre - filmed before the deaths were confirmed -he said: "I'm absolutely breaking up. All I'm hoping is that they are safe, that they are hiding and they are waiting for a time when it is safe to come out."

Yesterday Jenah's grandmother Shakuntna Bawa, of Leamington Spa, said: "The whole family is in shock."

US President Barack Obama said the attack was an "outrage."