Algeria’s President Abdelaziz Bouteflika is resigning after weeks of mass protests, according to state media report.
Mr Bouteflika, who has been in power for 20 years, had already dropped plans to seek a fifth term as opposition to his rule grew.
The powerful Algerian army had called for the 82-year-old to be declared incapable of carrying out his duties.
The ailing leader suffered a stroke six years ago and has rarely appeared in public since.
Car horns could be heard in the streets of the capital, Algiers, as hundreds celebrated the announcement.
People waved Algeria’s national flags and sang.
One man, Selmaoui Seddik, told Reuters: “God willing, we will have a 100% democratic transition, this is very important. We need to remove the whole previous regime and that is the hardest thing.”
One protest leader, Mustapha Bouchachi, said before the announcement that any decision by Mr Bouteflika to quit would still change nothing and that the protests would continue.
News of the resignation came in a statement carried on state news agency APS.
“The president of the republic, Abdelaziz Bouteflika, has officially notified the president of the constitutional council of his decision to end his mandate as president of the republic,” it said.
State TV then reported that this would be with immediate effect.
According to the constitution, the Senate speaker should take over as interim head of state until fresh elections are held.