Nairobi - A witness wounded in a blast in down town Nairobi says that the explosion occurred soon after a bearded man left a bag near her stall.
Irene Wachira spoke to The Associated Press from a Nairobi hospital bed on Monday. Wachira said the man came to the stall three times and acted as if he were interested in buying something. Wachira said the third time he came with a bag, he left it behind and then there was a blast.
Wachira described the man as "Arabic-looking" because of his relatively light skin. A doctor told AP that another person wounded in the blast said a Somali-looking man left behind the bag.
Police have not directly blamed terrorism, but Kenyan Prime Minister Raila Odinga called the explosion "a heinous act".
The explosion ripped through a building full of small shops in down town Nairobi on Monday, injuring at least 28 people, officials said.
A blast in Kenya's capital immediately conjures fears that al-Shabaab - 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. The prime minister, though, appeared to blame terrorism.
"This is a heinous act," Prime Minister Raila Odinga said while visiting the scene of the blast. "They want to scare us but we will not be scared."
The explosion sent dark smoke billowing out of a one-story building on a down town avenue named after Kenya's second president. The blast peeled back the front corner of the building's aluminium roof and sent items for sale in the shops - like shoes and clothes - scattered across the ground.
People with bloody wounds received medical care on the street as authorities tried to usher hundreds of people in the street away from the scene. Security blocked off areas around the building with yellow tape.
A hospital official said that at least 28 people were wounded, including four with serious injuries such as burns, fractures and deep lacerations. None of the victims had shrapnel in them, said Thomas Mutie, the acting chief executive at Kenyatta National Hospital.
The force of the explosion also shattered windows in the building, but a high-rise building with a glass exterior right next to the blast did not appear to sustain major damage.
A high-ranking police official said there were no obvious signs that the blast was caused by a terrorist's bomb. No ball bearings or nails - lethal shrapnel packed into bombs - were found, and officials were investigating the possibility that a faulty electrical line caused the explosion. The official said he could not be quoted by name.
"Let me not speculate this is a terrorist attack. It could be a wire fault," said another official Orwa Ojode, assistance minister for internal security.
Odinga, though, gave an energetic speech at the scene, telling Kenyans to support their security forces. Odinga said security would be improved down town, and made a reference to Somali militants despite the fact police said the blast wasn't caused by a bomb.
"They want to scare investors. They want to scare tourists," said Odinga, who is expected to run for president in Kenya's election next year. "We condemn the terrorists and tell them their days are numbered."
Al-Shabaab militants from neighbouring Somalia have long threatened to carry out substantial attacks in Kenya following Kenya's decision last October to send troops into Somalia to pursue al-Shabaab militants.
Kenya blamed a series of kidnappings on Kenyan soil last year on al-Shabaab, and the country saw tourist numbers plummet - especially around the coastal resort of Lamu - after the kidnappings.
Since October, Kenya has also suffered a series of grenade attacks. The latest happened on Saturday night in the sprawling Dadaab refugee camp. Six people were injured in two simultaneous grenades blasts, officials said.
Monday's explosion appeared to have been caused by a force larger than a grenade.