At least one person is killed and nine wounded after a suicide bomber detonates a grenade near a military base in Nairobi Friday.

The blast occurred in a Somali-dominated area.

Nairobi has blamed Somalia's al Qaeda-linked al Shabaab, which has threatened to retaliate after Kenya pursued the Islamists in Somalia in October.

One eyewitness says the police were powerless:

(SOUNDBITE)(English) UNNAMED EYEWITNESS, SAYING:

"So to make it worse, our police officers did nothing to stop the car from speeding past them."

The attack comes just hours ahead of a visit to Kenya by U.S. Secretary of State Hillary Clinton. Clinton's trip is expected to partly focus on U.S. security ties in the face of growing threats from Islamist militants.

Deborah Lutterbeck, Reuters.