NAIROBI — Kenya’s military caused the collapse of three floors of the Westgate Mall in the deadly terrorist siege, a top-ranking official disclosed Friday, as the government urged patience with the pace of an investigation that has left key questions unanswered
Seven days after 67 people were killed in the attack on the upscale shopping center, there is no clear word on the fate of dozens who have been reported missing and no details on the terrorists who carried it out.
The account of the roof collapse raises the possibility that the rescue attempt might have caused the deaths of hostages. An undisclosed number of people are feared to be buried in the rubble.
The official said autopsies will be conducted on any bodies found to determine the cause of death — from the militants or the collapse. The high-ranking government official spoke on condition of anonymity.
The official also confirmed that Kenyan troops fired rocket-propelled grenades in the mall, but would not say what caused the floors to collapse, whether the action was intentional, or if it was an accident.
Another official said rocket-propelled grenades fired by soldiers created a gaping hole in the mall’s roof and caused the floors to collapse. Four explosions had rocked the mall Monday and dark smoke poured out — the estimated time that the floors collapsed.
A soldier who was returning from the mall Tuesday while carrying a rocket launcher said that he had fired it inside.
The government has not said what caused the collapse. One official had suggested it was caused by a mattress fire in a department store.
Presidential spokesman Manoah Esipisu said structural engineers are examining the collapse. FBI agents, along with investigators from Britain, Canada, and Germany, are participating in the inquiry.
Police are trying to determine if the attackers stored ammunition in the mall before the attack, and investigators are tracing the ownership of a car that is believed to have been used by the gunmen.
Al Shabab said it carried out Saturday’s attack to punish Kenya for sending troops into Somalia to fight the Al Qaeda-linked militant group that had seized parts of that country for years before being dislodged from the capital, Mogadishu.
Amid the possibility that some of the attackers might have escaped during the evacuation of civilians from the mall, authorities have increased surveillance at border crossings and at the Nairobi airport.
Eight suspects are being held, Interior Minister Joseph Ole Lenku said. Three others were released.
The government says at least 61 civilians and six security forces were killed. At least five attackers were killed.
At the request of Kenya, Interpol issued a notice Thursday asking for help in capturing 29-year-old British-born fugitive Samantha Lewthwaite — not in connection with the mall attack, but over a 2011 plot to bomb holiday resorts in Kenya.
Known in British tabloids as ‘‘the white widow,’’ she was married to one of the suicide bombers in the 2005 attack on London’s transit system, and some speculate she was involved in the mall attack.