Kenyan police were on Sunday investigating an explosion in a Nairobi bus the day before that killed six people and wounded 30 others, the latest in a string of unclaimed attacks as the country marks 50 years of independence.
The death toll from the blast rose to six on Saturday after two injured people died from their wounds overnight, police said.
Nairobi police chief Benson Kibue said a suspect was being questioned over the attack on the 32-seat vehicle on Saturday, which came from the Eastleigh neighbourhood, dubbed "Little Mogadishu" because it is mainly populated by Somali immigrants and Kenyans of Somali origin.
"We lost two of the victims in hospital where about 30 others are still admitted," Kibue said. "We now have six people dead out of that incident."
Police were trying to determine whether the powerful explosion was caused by a grenade or an improvised explosive device and whether it was placed in the bus, carried by a passenger or flung from outside. The blast hit several cars near the bus, killing at least one of the motorists, according to witnesses.
"We have one suspect who was arrested soon after the incident. He is assisting us in the investigations," Kibue said.
On Sunday, the situation was calm in Eastleigh after police on late Saturday dispersed some rioters in the street where the blast took place. Police forces were not particularly visible in the area, nor in the rest of the Kenyan capital.
It was the fourth attack during a week in which Kenya marked its 50th anniversary of independence from Britain, leaving a total of 15 people dead since Tuesday.
No links have as yet been established between the attacks, none of which has been claimed by any group.
Suspicion for some of them, though, has focused on Kenya's two-year military intervention in neighbouring Somalia to oust Al-Qaeda-linked Shebab insurgents.