Kenyan Firefighter and Kenyan plain clothes police officers goes through the debris at a shop after an explosion on a busy road in Nairobi, Kenya, Monday, May 28, 2012. An explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-storey building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/Sayyid Azim) Photo: Sayyid Azim, Associated Press

A plain clothed police officer reacts as fire officers sort through the debris of a building after an explosion in Nairobi, Kenya, Monday, May 28, 2012. An explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-storey building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/ Khalil Senosi) Photo: Khalil Senosi, Associated Press

Medical personnal at Kenyatta National Hospital in Nairobi, Kenya, attend people injured in an explosion Monday, May 28, 2012. An explosion ripped through a building full of small shops in downtown Nairobi on Monday, wounding dozens of people, officials said. A blast in Kenya's capital immediately conjures fears that al-Shabab _ Islamist militants from Somalia _ have carried out an attack. Police officials indicated the blast was not a deliberate bombing _ given a lack of shrapnel at the scene _ but some sort of electrical accident. (AP Photo/ Khalil Senosi) Photo: Khalil Senosi, Associated Press

Medical personal at Kenyatta National Hospital in Nairobi, Kenya, attend to a woman injured in an explosion Monday, May 28, 2012. An explosion ripped through a building full of small shops in downtown Nairobi on Monday, wounding dozens of people, officials said. A blast in Kenya's capital immediately conjures fears that al-Shabab _ Islamist militants from Somalia _ have carried out an attack. Police officials indicated the blast was not a deliberate bombing _ given a lack of shrapnel at the scene _ but some sort of electrical accident. (AP Photo/ Khalil Senosi) Photo: Khalil Senosi, Associated Press

Medical staff wheel an injured person into Kenyatta National hospital, in Nairobi, Kenya, Monday, May 28, 2012. An explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-storey building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/ Khalil Senosi) Photo: Khalil Senosi, Associated Press

A plain clothed Kenyan police officer inspects the damage following an explosion which devastated the building in Nairobi, Kenya, Monday, May 28, 2012. An explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-storey building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/ Khalil Senosi) Photo: Khalil Senosi, Associated Press

A large crowd gather on the main street in Nairobi, Kenya, after an apparent explosion, Monday, May 28, 2012. attend to a woman injured in an explosion Monday, May 28, 2012. An explosion ripped through a building full of small shops in downtown Nairobi on Monday, wounding dozens of people, officials said. A blast in Kenya's capital immediately conjures fears that al-Shabab _ Islamist militants from Somalia _ have carried out an attack. Police officials indicated the blast was not a deliberate bombing _ given a lack of shrapnel at the scene _ but some sort of electrical accident. (AP Photo/ Khalil Senosi) Photo: Khalil Senosi, Associated Press

Kenyan Firefighters and Kenyan plain clothes police officer at a shop after the explosion on a busy road in Nairobi, Kenya, Monday, May 28, 2012. An explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-storey building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/Sayyid Azim) Photo: Sayyid Azim, Associated Press

Kenyan firefighter looks through the wreckage of a shop after the explosion on a busy road in downtown Nairobi, Kenya, Monday, May 28, 2012.An apparent explosion ripped through a building, full of small shops in downtown Nairobi on Monday, wounding an unknown number of people. The force of the blast ripped apart the one-story building's aluminum roof, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage. There was no immediate word on casualties or what caused the blast. (AP Photo/Sayyid Azim) Photo: Sayyid Azim, Associated Press