A grenade attack at a bus station in central Nairobi killed five people and wounded 69, the Kenya Red Cross said on Sunday.
There was no immediate claim of responsibility. The attack was similar to two strikes at a nearby bus station and a bar that killed one person and wounded more than 20 in October, soon after Kenya sent troops into Somalia to fight Islamist rebels.
Police blamed al Shabaab, the Somali militant group allied to al Qaeda that has pledged to carry out more reprisal attacks in Kenya until the east African country pulls its soldiers out of Somalia.
Witnesses say a grenade was tossed from a passing vehicle into the Machakos bus terminal near the central business district of Kenya's capital early on Saturday evening.
The Kenya Red Cross said on Sunday morning that 59 men and 10 women had been admitted to hospital, two of them were in intensive care, and five people were confirmed dead.
After the attack a fire blazed in a small crater at the bus station and police cordoned off the area where the body of a man lay facing upwards and dressed in a blue jacket and white trousers. Bystanders helped carry the wounded to ambulances.
Witnesses said they believed there were multiple blasts.
A Kenyan man who admitted to carrying out the October grenade attack on a Nairobi bus station admitted to being a member of al Shabaab. He was jailed for life.
The October attacks spooked Kenyans and security was beefed up in the capital at hotels, government buildings, restaurants, bars and shopping malls.
On Saturday morning, Kenyan police at a regular weekly briefing had again urged people to remain vigilant as the threat of attack from Somali militants remained.
There was no immediate reaction from al Shabaab. After the October strikes, a top al Shabaab official urged its supporters in Kenya to carry out a major strike, rather than tossing grenades at buses.
(Reporting by David Clarke; Editing by Louise Ireland)