Thousands of people are holding a pro-democracy rally in Algeria's capital Algiers, defying a government ban.
Scuffles broke out between the protesters and riot police and a number of people were reportedly arrested.
Algeria - like Egypt, Tunisia and other countries in the region - has recently witnessed demonstrations for greater freedoms and better living standards.
Public demonstrations are banned in Algeria because of a state of emergency still in place since 1992.
Heavy police presence
The protesters gathered at Algiers' 1 May Square on Saturday morning.
They chanted "Bouteflika out!" - in reference to the country's President Abdelaziz Bouteflika.
Some demonstrators waved copies of a newspaper front page with the headline about the ousting of Egyptian President Hosni Mubarak on Friday, Reuters reports.
About 30,000 police are reportedly deployed in and around capital, and extra police with water cannons are on stand-by.
At least 15 police vans, jeeps and buses were lined up at the square 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.
There is also said to be a crowd of supporters of President Bouteflika on the streets.
On Friday, the authorities stopped people from gathering to celebrate the fall of Mr Mubarak.
The authorities want to avert any popular uprising similar to those in Tunisia and Egypt, as some Algerians say it is time to seize the moment, the BBC's Chloe Arnold in Algiers says.
However, others here say there is less of an appetite for political upheaval than in other countries in the region, our correspondent adds.
Algeria has a bloody recent history: it is emerging from two decades of violence with as many as 250,000 people losing their lives in a conflict between security forces and Islamist militants.
Earlier this month, President Bouteflika 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.