Ali Benflis, the main challenger to incumbent Abdelaziz Bouteflika in Algeria's presidential election, on Sunday deplored violence that erupted at a rally for his rival east of the capital.
Campaigning for the April 17 election was launched two weeks ago, with the 77-year-old Bouteflika widely expected to clinch a fourth term without taking to the road due to health concerns.
Tensions over his re-election bid turned violent on Saturday when protesters stormed a campaign rally in Bejaia in the mainly Berber Kabylie region and torched his portraits before attacking a television crew covering the event.
Benflis condemned the violence, which prompted Bouteflika's campaign manager, former prime minister Abdelmalek Sellal, to scrap the rally.
"I regret that this campaign is taking place in a climate of tensions," Benflis said in a statement issued at a rally in his hometown of Batna, in another mainly Berber region, the Aures.
"I have to be honest and say nothing has been done to ensure it is taking place in a calm and serene" atmosphere, he was quoted as saying.
"I call for the respect of freedom of expression in all circumstances, a value which is the cornerstone of my policy of national renewal."
Bouteflika's campaign headquarters blamed the violence on the Barakat movement (Arabic for 'That's Enough') formed to oppose his candidacy.
Sellal and other Bouteflika aides have been doing the leg work for the president, who is too frail to campaign after a mini stroke last year confined him to hospital in Paris for three months.