Police in Angola have arrested at least 24 people for trying to stage a rally calling for the resignation of Angolan President Jose Eduardo dos Santos, according to media reports.
The rally was organised on Saturday in Luanda, the capital, by a youth movement without the support of major opposition parties, the Portuguese television station RTP reported.
It said around 200 youths gathered at Luanda's Independence Square at 1200 GMT before police stepped in to arrest a small group heading towards the presidential palace to demand the release of a protester allegedly arrested earlier on Saturday.
Dos Santos, who has held power in the oil-rich African nation for over 32 years, is one of several African leaders who have had to deal with anti-government protests inspired by uprisings in north Africa.
The crackdown left protesters, journalists and several police officers injured as they tried to persuade the demonstrators to stay on the authorised route, the channel reported.
"Against police guidance, some individuals forced the security cordon in an anarchical way, insulting passers-by and police officers and saying they wanted to the head to the palace," the police said in a statement quoted by Angop, the Angolan state news agency.
"That led to a climate of the violence, which led to the throwing of heavy objects and caused the injuries," it added.
Portuguese news agency Lusa cited one of the protest organisers who had been arrested as saying the police "acted with brutality" during an event authorised by the local government.
Dos Santos' MPLA party, which in 2002 won the 27-year-long civil war against UNITA and then obtained 82 per cent of the vote in the 2008 general election, has long been accused of mismanaging the country's oil revenues.
The government is accused of avoiding public scrutiny and doing too little to fight corruption.
An estimated two-thirds of Angola's 16.5 million people live on less than $2 per day in a country which is Africa's second-largest oil producer after Nigeria.
The MPLA is favourite to win a general election next year, but tensions are rising ahead of the ballot after UNITA, now the main opposition party, accused the government of stripping the national elections committee of any real power.