At least four people were killed in Cameroon's economic capital Douala on Monday when protesters angry over the high cost of living barricaded streets in the port city, looted shops and clashed with riot police.
The violence in the teeming city, a stronghold of opposition to President Paul Biya's 25-year rule, erupted after taxi drivers launched a strike to protest against petrol and fuel price hikes, which have pushed up prices of basic products.
Witnesses said riot police fired into the air and fired tear gas to try to disperse groups of protesters and looters across Douala, one of Africa's major west coast ports which also ships cocoa from the world's fourth biggest producer.
Officials from the Douala Port Authority were not available for comment. But reports indicated some port operations were slowed as the protests blocked the entry of some workers and arrivals of goods to be shipped. State radio reported protesters burned five trucks belonging to a timber exporter.
Protests have grown in the oil-producing state, one of sub-Saharan Africa's top 10 economies, after Biya announced last month his government would "re-examine" the constitution after what he said were popular calls for him to stay on past 2011.
The constitution requires Biya, who was 75 on February 13 and has ruled for 25 years, to step down in 2011.
Using car tyres, refuse and furniture which they set ablaze, youths wielding clubs barricaded streets, blocking traffic. Petrol stations and shops were looted and cars were torched, witnesses said. Soldiers were sent in to help restore order.
Police said at least four people had been killed.
"Two persons were pulled out of their car and beaten to death at Bonaberi neighbourhood. One man was burned to death when the Douala Five Council was set ablaze and another young man suffocated after inhaling too much tear gas," a senior police officer, who asked not to be named, told Reuters.
Monday's violence followed a clash in Douala on Saturday between police and opposition supporters protesting the plan to prolong Biya's rule. At least one protester was shot dead.
Organisers of the taxi drivers' strike, which was also supported in the capital Yaounde and other cities, demanded that the government reverse a recent hike in fuel prices.
"We cannot understand that our country produces petrol and we still buy petrol at the same price as people in non oil producing countries," said the president of the national taxi drivers' union SYNATA, Jean Collins Ndefossokeng.
Opposition parliamentarians accused the government of a heavy-handed response to the protests.
"Ever since President Biya made known his intention to amend the constitution, this city (Douala) has virtually been placed in a state of siege," said Jean-Jacques Ekindi, leader of the Mouvement Progressiste opposition party in Douala.
Demonstrators at the weekend also protested against the shutting down of private TV station Equinoxe, which had broadcast an interview with an opposition leader who accused Biya of wanting to rule for life and demanded a broad-based constitutional conference.
Biya's party won an overwhelming parliamentary majority last year in elections the opposition dismissed as a sham. This majority could allow it to change the constitution.