By Lamine Chikhi
ALGIERS (Reuters) - Algerian Prime Minister Abdelmalek Sellal will resign on Thursday to run the reelection campaign of the country's ageing President Abdelaziz Bouteflika, a source close to the presidency said on Wednesday.
Bouteflika, 77, registered his candidacy for the April 17 vote last week and spoke in public for one of the few time he has since suffering a stroke last year that raised opposition questions about his ability to govern.
Sellal will be replaced as premier by Energy Minister Youcef Yousfi, the source told Reuters.
Backed by the National Liberation Front (FLN) party and the army, Bouteflika is almost assured five more years in power. But his rare appearances have generated doubts about his health and about what happens if he is too sick to rule.
Sellal himself was the first to announce Bouteflika would run again. He did little to ease questions about the president's health when he said he would not need to campaign himself because there were plenty who could do that for him.
Since independence from France in 1962, observers say Algeria has been run from behind the scenes by a group of powerful FLN veterans, business leaders and army generals who have tussled for influence in backroom negotiations.
Any political handover in the key North African energy producer would come at a fragile time in a region still overcoming the turmoil following the 2011 "Arab Spring" revolts that toppled long-standing rulers in Egypt, Tunisia and Libya.
Algerian police earlier on Wednesday prevented opposition leaders from marching to demand a boycott of next month's election in protest against what they see as Bouteflika's unfair advantage in the race.
Opposition members, including figures from the secularist party Rally for Culture and Democracy (RCD) and the Islamist Movement for Peace and Society (MSP), believe Bouteflika's decision ends fair competition in the election.
Police stopped about 60 protesters from the RCD and MSP who were showing red signs with the word 'Boycott' and told them their demonstration was illegal.
"Why are they so afraid? It is a peaceful march, all we want is to convey a message that Bouteflika is too old, too ill to rule Algeria," said Abdelkader Ait Ali, one of those who tried to take part.
Official campaigning will start on March 23 and international observers, including from the European Union, are invited to monitor the April 17 election.
A week ago, the police prevented a movement called Barakat, a small group of protesters including journalists, from marching in the capital Algiers to call for a boycott.
(Reporting by Lamine Chikhi; writing by Patrick Markey; Editing by Tom Heneghan)