11 March 2012 Last updated at 09:14 ET

Kenya blames al-Shabab for deadly Nairobi grenade attack

Passers-by helped carry the wounded to ambulances outside

At least six people have been killed and more than 60 injured in an attack at a busy bus station in the Kenyan capital, Nairobi.

Four grenades were thrown from a passing car, Internal Security Minister George Saitoti said.

Militants of the Somali Islamist group al-Shabab are suspected of being behind the Saturday evening attack, he said.

It was similar to attacks in October when grenades thrown into a bar and bus station killed one and injured many.

That attack happened just days after the Kenyan military had crossed into Somalia to fight the Somali militants and was also blamed on al-Shabab.

Crater blaze

No group has said it carried out Saturday's attack, which occurred at about 19:30 local (16:30GMT).

Analysis

Will Ross BBC News, Nairobi

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In recent months there have been numerous attacks close to the Kenyan-Somali border.

Officials have blamed these on al-Shabab sympathisers acting in response to Kenya's military operation.

Across the border in Somalia, there has been heavy fighting between the Islamist militants and Ethiopian forces.

These were the fiercest clashes since the Ethiopian army last November joined the Kenyan and African Union troops in the fight against al-Shabab.

After the explosions, a fire blazed in a small crater at the Machakos bus station and bystanders helped carry the wounded to ambulances, Reuters news agency said.

Kenyan Vice-President Kalonzo Musyoka later called for calm.

"This is an attack by people who think they can puncture the resolve of Kenyan people to fight against terror," Mr Musyoka told reporters on Sunday outside the Kenyatta hospital which is treating the injured.

"It is a difficult moment, but it should strengthen our resolve," he said.

Threats

There has been a string of small arms attacks and explosions on Kenyan soil ever since Kenyan troops crossed the Somali border.

Kenyan soldiers fighting al-Shabab in Somalia are due to be integrated into the African Union peacekeeping force next week.

The group has threatened to attack Kenya on several occasions.

Police there recently arrested several people over an alleged plot to blow up a hotel on the Kenyan coast.