Kenya's President Uhuru Kenyatta has announced a formal inquiry into apparent security lapses during the deadly assault on Nairobi's Westgate mall by Islamists, in which at least 67 were killed.

As shopkeepers complained their stores in the upmarket shopping centre had been completely looted, Kenyatta announced an investigation into the security implications of the massacre claimed by the al-Shabab, an Al-Qaeda-linked Somali group.

"We are putting in place a commission of inquiry to see if we could have done things better, to see if there were lapses," Kenyatta said at inter-faith prayers led by leaders from the Muslim, Christian and Hindu communities.

Politicians from parliament's national security and defence and foreign relations committees visited the mall on Monday afternoon, picking their way through shattered glass and pools of congealed blood in the main hall.


Thirty-nine people are still missing, according to the Red Cross, a week after Kenyan forces brought an end to the four-day bloodbath.

Kenyan and foreign investigators continue to comb the carcass of the mall for clues on the perpetrators and their operating methods.

Asman Kamama, the chairman of the parliamentary joint committee, said the team of lawmakers was expecting to quiz security chiefs on Thursday.

The probe is expected to last several weeks at least.

Shopkeepers allowed back into the mall to check on their premises painted an apocalyptic scene, saying it stank of corpses and that the first floor of the mall was completely burned.

"There's a really bad stench in there of the dead bodies and blood all over the place," Pardeep Rehal, a bookstore owner, told AFP.

Many shopkeepers accused the Kenyan forces of looting their stores.

Part of the rooftop parking of the mall collapsed after heavy explosions and a fierce fire, leaving the key area where the insurgents are understood to have made their final stand - along with possible hostages - buried under tonnes of concrete slabs and rubble.

Experts predict that the terrorist attack will cost Kenya's economy $200 to $250 million in lost tourism revenue.

Moody's Investors Service and the World Travel and Tourism Council said the extremist assault will slow growth of Kenya's GDP by 0.5 percent. Tourism generates 14 percent of Kenya's GDP and employs 12 percent of its workforce.

According to the council, tourism is Kenya's largest earner of foreign exchange after tea and coffee exports, generating $4.7 billion in 2011.

Kenya is Africa's fifth largest tourist destination, welcoming approximately 1.8 million visitors each year.

Meanwhile, rights groups condemned comments by the politicians that they would also "rethink" Kenya's hosting of some half a million Somali refugees.

Somali refugees in Kenya, including many who fled the al-Shabab, have expressed fears they will be targeted in reprisal raids.

"While protecting Kenyans from security threats is an urgent priority, Human Rights Watch is concerned about reports that some members of parliament have called for the closure of the Somali refugee camps in Kenya," said HRW's Gerry Simpson.

"These camps are currently home to over 400,000 refugees ... Forcing them back to a country still wracked by widespread violence and insecurity would not only breach Kenya's obligations under international law, but could inflame further instability in Somalia."