David Cameron has warned the UK to brace itself for "more bad news" after the deaths of three British nationals in the Nairobi terror attack as the Kenyan authorities mounted an operation aimed at ending the siege.
The Prime Minister said the UK had offered Kenya assistance, including intelligence co-operation, in response to the rampage by Islamic extremists in an upmarket shopping centre which has left scores dead and many more injured
Somali-based militant group al-Shabaab claimed responsibility for the attack, with about 10 to 15 gunmen believed to be holed up in the Westgate mall holding a number of captives more than 24 hours after the violence began.
A sombre Mr Cameron said: "It is an absolutely sickening and despicable attack of appalling brutality. What we know is that three British nationals have been killed." He added: "Because the situation is ongoing we should prepare ourselves for further bad news. Our thoughts also should be with the Kenyan government and the Kenyan people at this time."
Mr Cameron said he had offered the Kenyan authorities "every assistance" in a call to president Uhuru Kenyatta, who lost members of his own family in the attack. The Prime Minister was at pains to stress that the perpetrators did not represent the majority of Muslims but had carried out the atrocity "in the name of terror, violence and extremism".
UK staff from Addis Ababa in Ethiopia travelled to assist locally-based officials with the efforts in Nairobi and a rapid deployment team was sent from London, the Foreign Office said. Foreign Secretary William Hague chaired a meeting of the Government's emergency committee Cobra to co-ordinate the response to the situation.
Labour leader Ed Miliband offered his support to the Government and said: "Those who carried out this attack will be condemned across the globe. The cold-blooded killing of innocent women, children and men is as despicable as it is shocking."
An al-Shaabab spokesman told Channel 4 News that westerners would not be safe in Kenya until the country pulled its forces out of Somalia. He said: "Kenyans have blood on their hands. Anyone who is prepared to come to Kenya must be prepared to face the reality, and we don't fear Europeans and Americans because we are not weak."
Kenya's Red Cross said the death toll from the militant attack on the mall had risen to 68 and president Kenyatta's nephew and his fiancee were among those killed.
"These are young lovely people I personally knew and loved," the president said, promising retribution against the terrorists. "They shall not get away with their despicable and beastly acts. Like the cowardly perpetrators now cornered in the building, we will punish the masterminds swiftly and indeed very painfully."