Police fired tear gas Wednesday to disperse youths rioting in central Mozambique after reports of forced conscription as the military battles a revived rebel group, a rights group and residents said.

Security forces clashed with protesters in central city Beira, according to the Human Rights League (LDH).

"There is a revolt on the part of the population. The police have been using tear gas," LDH representative Helder Jafar told AFP.

There were "many injuries and arrests", he added.

Residents confirmed police fired tear gas in several outlying neighbourhoods of Beira while protesters threw stones at a police station.

"There are barricades in the streets and cars are being burnt," said Stella Santos, who lives in Manga, one of the affected Beira neighbourhoods.

"They say they (the military) are conscripting the young people," she told AFP.

Local newspapers reported that the military was going from door to door forcibly conscripting youngsters to fight against a revived Renamo insurgency elsewhere in the central Sofala province.

Some Beira residents who asked to remain anonymous told AFP that the conscription was a "fact", and that the military used "kidnappings" to increase its numbers.

"The population is furious. They want to burn any car that passes through the city," said a student.

Three neighbourhoods were believed to have been affected.

Authorities slammed the reports as "a rumour aimed at discrediting this sacred, patriotic duty to the fatherland by the youth".

"It is not true that the National Defence Ministry or other security forces are undertaking forced recruitment for military service," the department said in a statement.

Though Mozambican law allows for involuntary conscription of youths aged 18 years and above, in practice, anyone who does not wish to serve can get out of the draft if they provide a justification.

The 13 000-strong force is therefore almost exclusively staffed with volunteers as a soldier's stipend is enticement for many of the country's poor, unemployed youths.

Since April this year the army has waged ongoing battles against Renamo guerrillas around 200 kilometres (120 miles) north of Beira in the Gorongosa district, as well as around the town of Muxungue to the south.

The Beira protests come just a week after the candidate for opposition party the Mozambique Democratic Movement (MDM) was elected mayor in local elections.

The city is only the second not controlled by the ruling Frelimo party.