At least four people, including a Kenyan policeman, have died in clashes between police and street hawkers in the capital, Nairobi.
The hawkers set alight power transformers
The trouble started when police tried to arrest illegal street traders in the River Road area.
The BBC's Anne Mawathe says when one of the vendors tried to escape the police opened fire, infuriating the traders.
They rioted and set fire to power transformers, which the police had to put out with piles of earth.
Local television reports that some of demonstrators have serious bullet wounds.
Police commander Julius Ndegwa described the clashes as an "unfortunate incident", AFP news agency reports.
Our correspondent says confrontations between hawkers and the police are not unusual in Nairobi as the traders are not allowed to trade in the central business areas of the capital.
They had come into the centre to take advantage of the public holiday as Kenyans celebrate their independence day, she adds.