Kenya mall siege: 'final assault' begins

Witnesses in Nairobi report huge blast as security forces enter shopping centre where armed militants are holding 30 hostages

Kenyan security forces, including commando teams and military helicopters, have launched a "final assault" on the luxury shopping mall in Nairobi where a group of armed militants were holding around 30 hostages.

As night fell in Nairobi a huge blast reverberated around the Westgate mall where the attackers – thought to be members of the Somali jihadist group, al-Shabaab –had been holed up since shooting their way into the shopping centre on Saturday.

The explosion was the loudest heard since the attack began and was followed by a long silence. "This will end tonight. Our forces will prevail," the Kenyan government's Disaster Operation Centre said late last night.

The carnage in and around the four-storey building, where heavily-armed fighters opened fire on weekend shoppers on Saturday lunchtime, claimed at least 68 lives with 175 people injured. That toll, which rose steadily throughout Sunday, was expected to climb higher.

Kenya's president, Uhuru Kenyatta, who lost a nephew in the attack, promised to punish those behind it "swiftly and painfully," and said Kenya "would not relent on the war on terror".