Riot police have been deployed in the centre of the Algerian capital, Algiers, ahead of a planned anti-government rally.
The government has banned the protest, but opposition and rights groups say they intend to go ahead with the march.
Algeria - like other countries in the region - has recently witnessed demonstrations for greater freedoms.
On Friday, police stopped people from gathering to celebrate the fall of Egypt's President Hosni Mubarak.
The BBC's Chloe Arnold in Algiers say the authorities want to avert any popular uprising similar to those in Tunisia and Egypt.
"We are ready for the march," Mohsen Belabes, a spokesman for the small Rally for Culture and Democracy (RCD) opposition party, said.
"It's going to be a great day for democracy in Algeria," he told Reuters news agency.
'Armoured vehicles'
Demonstrations are banned in Algeria because of a state of emergency which has been in place since 1992.
A heavy police presence is normal in Algeria but far more officers than usual were in place hours before the start of the protest at 1100 local time (1000 GMT), Reuters reports.
At least 15 police vans, jeeps and buses were lined up at 1 May Square, where the march is due to start, and about the same number on a nearby side-street outside the city's Mustapha hospital.
Small military-style armoured vehicles were also parked at junctions around the city.
Earlier this month, Algerian President Abdelaziz Bouteflika reportedly said the country's state of emergency would be lifted in the "very near future".
Mr Bouteflika made the announcement at a meeting with government ministers in the capital Algiers, according to the country's state-run media.
He said protests would be allowed everywhere in the country except in the capital.
http://www.bbc.co.uk/news/world-middle-east-12438015
