By Lamine Chikhi
ALGIERS (Reuters) - Algerian police prevented opposition leaders from marching on Wednesday to demand a boycott of next month's election, in which President Abdelaziz Bouteflika is seeking a fourth term in power.
Bouteflika, 77, registered his candidacy for the April 17 vote last week, one of the few times he has spoken in public since suffering a stroke last year that has raised opposition questions about his ability to govern.
Opposition leaders, including 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 protesters from the RCD and MSP - some 50 or 60 people - who were showing red signs with the word 'Boycott', saying 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.
Islamist leader Abdallah Djaballah told reporters: "Bouteflika needs a rest, he is tired."
Nearby, a group of the president's supporters shouted "Yes for a fourth term for Bouteflika".
Official campaigning will start on March 23, and international observers, including from the European Union, are invited to monitor the election.
With the backing of the National Liberation Front (FLN) party and the army, Bouteflika is almost assured five more years in power. But his scarce public appearances have generated doubts about his health and about what happens if he is too ill to rule.
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.
Large-scale protests are rare in Algeria where an elite of FLN veterans and army intelligence generals, known as "The Power", has called the shots since independence from France in 1962.
Many Algerians are wary of upheaval, with memories of civil war with Islamist fighters in the 1990s still fresh. More than 200,000 people died in that conflict.
Any political handover or transition in the key North African energy producer would come a fragile time in the region, still overcoming turmoil that followed the "Arab Spring" revolts against long-standing rulers in Egypt, Tunisia and Libya three years ago.
(Editing by Patrick Markey and Mark Trevelyan)