BUJUMBURA, Feb 19 (Reuters) - Burundian police fired teargas to disperse about 90 journalists protesting against the detention of a colleague accused of complicity in a 2011 gun attack, in a case that has raised concerns about a clampdown on media in the east African nation.
Police said they used force because the demonstration in the capital Bujumbura was illegal.
Journalists have been targeted in a wave of detentions. Human Rights Watch said last year the government was trying to restrict efforts by independent media and civil society to denounce violence blamed on the state.
Deadly clashes last year between security forces and former militia fighters rocked the country, which had enjoyed relative peace since rebels laid down arms and joined the government in 2009 after two decades of civil war.
"This is a flagrant violation of the country's constitution which recognises the freedom of expression and assembly," said Burundi journalists' union chairman, Alexandre Niyungeko, of the police response to Tuesday's march.
Hassan Ruvakuki, a reporter for Radio France Internationale (RFI) and a Burundi independent radio station, was arrested in November 2011, accused of involvement in an attack by militants on the eastern town of Cankuzo that was launched from neighbouring Tanzania.
The prosecution had said Ruvakuki was complicit in the attack because he had travelled to Tanzania earlier that month and interviewed the rebel group's proclaimed leader. He was sentenced to life in jail last year.
In January, a court reduced his sentence to three years in prison, finding him guilty of a less serious offence. (Reporting by Patrick Nduwimana; Editing by George Obulutsa and Jeremy Laurence)