NAIROBI (Reuters) - Islamist militants were holed up with hostages on Sunday at a shopping mall in Nairobi, where at least 59 people have been killed in an attack by the al Shabaab group that opposes kenya's participation in a peacekeeping mission in neighboring Somalia.

A volley of gunfire lasting about 30 seconds interrupted a stalemate of several hours, a Reuters witness said, speaking from near the Westgate shopping centre that has several Israeli-owned outlets and is frequented by expatriates and Kenyans.

Foreigners, including three Britons and two diplomats - one from Canada and another from Ghana - were killed in Saturday's attack at the upmarket mall, claimed by Somali group al Shabaab.

Shortly after the shots were fired, troops in camouflage ran crouching below a restaurant terrace along the front of the building that had been buzzing with customers when assailants charged in. One witness said they first told Muslims to leave.

For hours after the brazen attack, the dead were strewn around tables of unfinished meals. At one burger restaurant, a man and woman lay in a final embrace after they had been killed, before their bodies were removed. Pop music was left playing.

Scores of Kenyans gathered at a site overlooking the mall, awaiting what they expected to be a violent denouement. "They entered through blood, that's how they'll leave," said Jonathan Maungo, a private security guard.

President Uhuru Kenyatta, facing his first major security challenge since a March election, said some of his close family members were among the dead, and vowed to defeat the militants.

"We have overcome terrorist attacks before," he said.

The assault was the biggest single attack in Kenya since al Qaeda's East Africa cell bombed the U.S. Embassy in Nairobi in 1998, killing more than 200 people. In 2002, the same militant cell attacked an Israeli-owned hotel on the coast and tried to shoot down an Israeli jet in a coordinated strike.

Al Shabaab's siege underlined its ability to cause major disruptions with relatively limited resources.

"In terms of capacity, while the group has grown considerably weaker in terms of being able to wage a conventional war, it is now ever more capable of carrying out asymmetric warfare," said Abdi Aynte, director of the Mogadishu-based Heritage Institute of Policy Studies, a regional policy and security think tank.

COSTLY FOR KENYA

Aynte also said the raid showed "a major failure on the part of the Kenyan security services", which had not detected an operation that must have taken several months to plan. Other experts said Western agencies had also not picked it up.

Interior Minister Joseph Ole Lenku told reporters the death toll had risen to 59, and that security forces were doing everything they could to rescue hostages still inside the mall.

He added that 175 people had been taken to hospital after an assault that could prove a costly setback for east Africa's biggest economy, which relies heavily on tourism revenues.

Kenya's deputy president, William Ruto, asked judges at the International Criminal Court in The Hague to allow him to return home to help deal with the siege and its aftermath.

He and Kenyatta face charges of crimes against humanity for their alleged role in coordinating violence that swept Kenya in the aftermath of the country's contested 2007 elections.

The dead in Saturday's assault included children, and the wounded ranged in age from 2 to 78. Many victims were at a cooking competition when assailants opened fire on them, witnesses said. More than 1,000 people were evacuated.

The focus of attention on Sunday was on Nakumatt supermarket, one of Kenya's biggest chains.

Source: Chicagotribune