Major explosion at Nairobi Mall

Kenyan security forces are still battling to end a standoff with Somali al-Shabaab terrorists.

Smoke can be seen billowing out of the Westgate Shopping Mall in Nairobi on 23 September 2013 after an explosion. Picture: via Twitter

NAIROBI - A huge explosion and gunfire has been reported at Nairobi's Westgate Shopping Mall where Kenyan security forces are still battling to end a standoff with Somali al-Shabaab terrorists.

Al-Shabaab militants behind the terrorist attack have reportedly said they are prepared to die to advance their attack on the country's regime.

A group of between 10 and 15 militants stormed the mall on Saturday and began shooting civilians indiscriminately killing at least 69 and wounding 175 others.

South African businessman James Thomas is among those who were killed.

Kenya's interior minister Joseph Ole Lenku says the official death toll from the attack so far remains at 59, with 175 people injured while the Red Cross is reporting 69 people have been killed.

The ministry has disputed higher tolls being given by some organisations saying they could be incorrect because of double counting.

It says security has been stepped up at all of the country's border points including airports and seaports.

Dozens of people are still unaccounted for but officials have warned Kenyans against providing false information to authorities on people they believe are trapped in the mall.

Kenyan police are urging people to stay away from the scene as they intensify operations to end the siege.

The country's military says only about 10 people are still being held hostage. Others are thought to be hiding in the centre.

Lenku said "a few" people are still being held hostage.

"Our disciplined forces have been extremely careful to find the balance between neutralising the attackers and getting as many people to safety as possible."

There have also been unconfirmed reports that some of the hostages may be strapped with explosive devices.

Reuters photographer Noor Khamis says reports that the hostages are wired to explosives is complicating the Kenyan military offensive.

"One of the security people has said that it looks like some of the hostages may be strapped to explosives. This is very dangerous."

A spokesman for al-Shabaab, which has demanded Kenya pull its troops out of neighbouring Somalia, warned they would kill hostages if Kenyan security forces tried to storm their positions.

"Israelis and Kenyan forces have tried to enter Westgate by force but they could not. The mujahideen will kill the hostages if the enemies use force," said Sheikh Ali Mohamud Rage.

On Twitter, the group posted: "As the operation gathers momentum inside #Westgate, the Mujahideen are for the third day still in full control of the situation on the ground."

Survivors' tales of the military-style assault by squads of attackers hurling grenades and spraying automatic fire has left little doubt the hostage-takers are willing to kill.

Previous raids around the world, including at a desert gas plan in Algeria nine months ago, suggest they are also ready to die.

'ATTACKERS WILL BE PUNISHED'

Meanwhile, Kenyan President Uhuru Kenyatta said those responsible will be punished.

"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. I call on Kenyans to stand courageous and united."

Asked at a news conference about whether captives had been wired with explosives, Kenyatta declined to comment.

The President, who lost a nephew and his nephew's fiancé in the attacks, vowed to hold firm in the "war on terror" in Somalia and said cautiously that Kenyan forces could end the siege.

"I assure Kenyans that we have as good a chance to successfully neutralise the terrorists as we can hope for. We will punish the masterminds swiftly and painfully."

But a military spokesman for al-Shabaab said his group had nothing to fear.

"Where will Kenyatta get the power with which he threatens us?" said Sheikh Abdiasis Abu Musab.

The assault is the biggest single attack in Kenya since al-Qaeda's East Africa cell bombed the US Embassy in Nairobi in 1998, killing more than 200 people.

Kenya sent troops into Somalia in October 2011 to pursue militants whom it accused of kidnapping tourists and attacking its security forces.

Al-Shabaab's last big attack outside Somalia was a twin assault in Uganda which killed 77 people who were gathered to watch the 2010 World Cup final.