Kampala  - Three people were confirmed dead and dozens more were feared dead or injured after an office block collapsed Friday in the centre of the Ugandan capital Kampala.

The foundations of a new construction being dug between high-rise buildings caved in, pulling down a three-storied block leaving dozens of shopkeepers and shoppers trapped.

"We have not yet found the cause of the collapse - all we're trying to do is to save the lives of the people trapped under the rubble," said police spokeswoman Judith Nabakooba.

Bukedde FM government radio said people trapped were sending desperate messages on cellphones.

A witness told Deutsche Presse-Agentur dpa that "at least 200 people" were trapped after the building slowly subsided down the side of the newly-dug foundations.

By early evening, bulldozers had been brought in to begin clearing rubble and concrete at the site, in one of Kampala's busiest areas.

Many lives are lost each year in Kampala in accidents involving collapsed buildings which the government blames on poor supervision by city authorities. (dpa)