Polls have opened in Algeria where incumbent President Abdelaziz Bouteflika is seeking a fourth term in office.
The 77-year-old leader has rarely appeared in public since suffering a stroke last year and has not campaigned personally ahead of the election.
Bouteflika, who is favourite to win, is facing five other candidates.
Opposition parties have held protest marches and called for a boycott, describing the election as a sham.
They say Bouteflika is unfit to run because of his health problems.
Three other presidential candidates pulled out of the race soon after Bouteflika’s candidacy was announced, saying the result was now a foregone conclusion.
His re-election bid has spawned a protest movement called Barakat, meaning “Enough”, which have been holding demonstrations around the country.
Police violently broke up a protest organised by the group in the capital, Algiers, on Tuesday and arrested some of its members, the AFP news agency reports.
More than 260,000 police have been deployed to protect 50,000 polling booths, it reports.
Bouteflika’s main challenger, Ali Benflis, said he would not tolerate any attempt to rig the election in favour of the president.
“In case there is fraud I will not shut up. This does not mean we will push for chaos, because we have opted for stability,” he said.
Bouteflika took office in 1999 when Algeria was still caught up in a civil war between the military and Islamist militants and has been credited by supporters for curbing the conflict and restoring some economic stability.
He scrapped constitutional rules in 2008 limiting him to two terms in office.
Bouteflika won elections the following year with 90 per cent of the vote.