ALGIERS: Security forces arrested 41 people during angry protests that rocked Algeria's capital against ailing President Abdelaziz Bouteflika seeking a fifth term, authorities said Saturday.
Police fired tear gas on Friday to block a protest march on the presidential palace, prompting demonstrators to respond with stone-throwing.
The Directorate General for National Security (DGSN) said Saturday it had detained 41 people over "public disorder, vandalism, damage to property, violence and assault".
Despite the arrests, protests around the country were largely tolerated by authorities, even in the capital, where demonstrations have been strictly banned since 2001.
The police did not give an estimate of the number of protesters, but a security official speaking on condition of anonymity told AFP some 20,000 people had demonstrated nationwide, around a quarter of them in Algiers.
The official said 38 of the arrests were in the capital, and that no security personnel had been wounded.
Some demonstrators in Algiers scaled the outside of a building and tore down a poster bearing the portrait of Bouteflika, the country's 81-year-old president.
French-language daily El Watan said crowds also gathered in the city of Ouargla where "thousands of demonstrators chanted 'the people want the fall of the regime'," the slogan of the Arab Spring revolts of 2011.
Activists had used social media to call for nationwide protests against Bouteflika after Friday's weekly Muslim prayers.
Analysts on Saturday played up the scope of the demonstrations in several cities as unprecedented as well as the absence of any serious incidents.
"At the national level and with this size, taking place simultaneously and with the new use of social media, I think it's a first," said Louisa Dris-Ait Hamadouche, a professor of political science at Algiers University.
A foreign diplomat posted in Algiers, speaking on condition of anonymity, said the scale of the demonstrations in defiance of the ban signalled "a change in the political order".
Dris-Ait Hamadouche praised both the demonstrators and the security forces for their apparent restraint.
"Algerians have shown that they can demonstrate without turning it into a riot," she said. As for police, "they were no doubt given instructions to avoid any escalation".
The authorities must have wanted "to avoid any spillover that could damage Algeria's image as a stable state", she said.
Bouteflika, who uses a wheelchair and has rarely been seen in public since suffering a stroke in 2013, announced on February 10 that he will run for another term in an April presidential election.
He spoke of an "unwavering desire to serve" despite his health constraints and pledged to set up an "inclusive national conference" to address political and economic reforms.
The president's office has announced that Bouteflika will travel to Switzerland on Sunday for "routine medical checks" ahead of the April 18 election.
He has had a long battle with illness and has frequently flown to France for treatment.
Bouteflika is Algeria's longest-serving president and a veteran of its independence struggle, who has clung to power since 1999 despite his ill health.
When the Arab Spring erupted in January 2011, Bouteflika rode out the storm by lifting a 19-year state of emergency and using oil revenues to grant pay rises.