Opposition supporters have clashed with the police in the industrial town of Douala and south-western Buea in Cameroon, demanding the president steps down.
Paul Biya had earlier announced that he wants to change the country's constitution, to prolong his 25-year rule.
Opposition supporters reject the proposal.
In Yaounde, Cameroon's capital, the police guarded the streets and petrol stations remained closed for fear of being attacked on Wednesday.
A day earlier, the freight transport union had called off a month-long strike after successfully forcing the government to roll back fuel prices.
The strike had brought the oil-producing nation to a standstill.
Biya's government had agreed to reduce the price of a litre of petrol to 594 CFA Francs ($1.36) from 600.
Thousands of protesters in Douala, Buea and Yaounde shouted slogans against Biya and demanded that he step down after his term ends in 2011.
One demonstrator said: "Biya has gone too far, he must go. We also want an overall reduction in commodity prices."
Ernest Karngong, a businessman, said: "Shops and stores remain shut, taxis are not back on the streets, not even motorcycles. A few private car owners who ventured out found their windscreens shattered and they returned home."
The demonstrators shouted, "We're fed up" and called for all basic goods to be sold at cheaper prices.
The riots in Cameroon were the worst in the past 15 years.
At least eight people were killed in the last four days and rioters blocked all major streets in Cameroon with barricades of burning tyres and timber.
Police used tear gas to disperse the stone-throwing demonstrators and bring the situation under control.