Patrick Onyango, Uganda's deputy police spokesperson told Xinhua in an interview that the fatal accident occurred after the driver of a truck lost control and swerved off the road at Walwanda Mosque junction.
"The truck failed to negotiate a corner. Six people died on the spot and the other on the way to the hospital," said Onyango.
He said the 17 injured were admitted at Buvuma Health Centre IV and Kawolo hospital for medical care and treatment.
The police spokesperson said the bodies of the deceased who were yet to be identified were taken to Buvuma Health Centre.
Uganda registers about 20,000 accidents each year, with some 2,000 deaths, making it one of the countries with the highest road traffic death rates, according to police statistics.