Police have fired tear gas to disperse tens of thousands of demonstrators marching through central Algiers against Abdelaziz Bouteflika’s bid for a fifth term in office. Other marches in cities around the country including Oran, Constantine, Setif, Tizi Ouzou and Bouïra drew thousands more angry at the ailing president’s attempt to prolong his 20 years in power, local media reported. Riot police fired tear gas to disperse a group of around 200 young people, around 1.5km from the presidential palace in Algiers. According to a police toll, 56 officers and seven demonstrators were hurt and 45 arrests made in the capital. Witnesses reported a number of people wounded after being hit by batons, tear gas grenades and stones thrown by police back at demonstrators who had initially hurled them at officers. Gathering in the capital after Friday prayers, protesters, some carrying roses, chanted “bye bye Bouteflika”, “peaceful, peaceful” and “the people reject Bouteflika and Saïd”, a reference to the 81-year-old president’s brother who is widely believed to be ruling in his name. “The people want the fall of the regime,” some of those looking to converge at the Place de la Grande Poste in the city centre shouted. Police helicopters circled overhead. “There’s a huge crowd,” said Saïdani Meriem from the opposition party Jil Jadid, sharing photos of streets filled with protesters waving Algerian flags as they marched down the Rue Hassiba Ben Bouali in Algiers, where protests have officially been banned since 2001. “It’s definitely a historic day,” Meriem said. “The president needs to respond to this mass movement, by first and foremost stopping his power grab.” Hamdane Salim, a 45-year-old public sector worker, said Algeria’s youth was “demanding a valid president who can talk to the people”. Nahla Djabi, another marcher, said the protesters were heading “towards the central post office, and from there the presidential palace”. “The atmosphere is very relaxed,” he said. “There are plenty of families, women, children. It’s calm for the moment. It’s very joyous. We have hope, a lot of hope.” Chloe Teevan, a Maghreb specialist at the European Council for Foreign Relations, said many people took to the streets even before the end of prayers. “There appear to be tens of thousands. There have been reports of police blocks and some use of tear gas, but by and large the protests are proceeding peacefully,” she said. Bouteflika’s opponents say the president, who has been seen in public only a handful of times since he suffered a serious stroke in 2013, is no longer fit to lead and that Algeria is being run by a group of advisers, including Saïd. Authorities insist the president, who came to power in 1999, still has a firm grip on public affairs. “Bouteflika was sick when he sought a fourth term in 2014, but his medical results for the past five years were good,” Prime Minister Ahmed Ouyahia told parliament on Thursday. Bouteflika flew to Switzerland on Sunday for what his office called routine medical checks in the run-up to the election. Presidential candidates must pass a medical aptitude test and can be declared ineligible if they fail. The mass protests in more than 30 cities began last Friday after the president’s National Liberation Front confirmed him as its candidate in the 18 April election. It appears to have broken a long-standing taboo against national public dissent in Algeria. The Mouwatana opposition group faces significant hurdles in mounting an effective challenge, with Bouteflika having already secured the endorsement of several political parties, trade unions and business groups and no obvious successor apparent. A veteran of Algeria’s independence struggle against colonial power France, Bouteflika is credited with helping end the country’s decade-long civil war between government forces and Islamist militants, in which an estimated 200,000 people died, in 2002. Many Algerians have since tolerated a restrictive political regime and omnipresent state security service in exchange for relative calm and stability. The scale of this week’s protests, despite the reluctance of the state broadcaster and private channels owned by pro-government media magnates to cover them, has taken observers by surprise.