A blast in central Nairobi killed at least one person on Monday morning and police said they believed it could have been a suicide bombing.
Passersby said a small bomb had gone off in a waste paper bin at about 8 a.m. (0500 GMT). A bloodied corpse lay on the pavement nearby, a Reuters witness in the Kenyan capital said.
"We believe it is a suicide bomber," a senior policeman who did not want to be named, told Reuters. "We are always peaceful. This sort of attack is very unusual for Nairobi."
Various people were injured in the attack on the normally busy street and had been rushed to the country's main hospital, he said.
"It was a very loud explosion. I thought it was a tyre burst but it was louder than that," Langat Justice, a 20-year-old student who witnessed the explosion, told Reuters near the chaotic scene.
"This is very unusual for Nairobi. Maybe this was a terror attack, we don't know," he added, as hundreds of people milled around and policemen tried to push them back from the scene.