Police on Friday fanned out across the DR Congo capital Kinshasa and other main cities as thousands of opposition supporters marched seeking the withdrawal of electronic voting machines in a long-delayed election due at the end of December.
The regime of President Joseph Kabila in a rare gesture authorised the protest rallies but AFP correspondents said security forces were deployed in strength in Kinshasa, the key eastern cities of Goma and Bukavu and Bunia in the northeast.
Thousands marched in central Kinshasa shouting "We will fight to the death", and "Voting machine equals cheating machine," an AFP journalist said.
Former warlord Jean-Pierre Bemba and regional baron Moise Katumbi have been barred from standing for the top job in a move that raised howls of protest from their powerful blocs of supporters.
Bemba has asked people to rally in droves to protest against "the greatest electoral fraud ever with electronic machines that have not been tested anywhere in the world."
Katumbi meanwhile in a video exhorted his supporters to "stage a massive march to say no to the electronic machines and no to corruption."
But police in Lubumbashi, a Katumbi stronghold and the country's second city, warned residents that "anyone who dares to march will find the police on their path."
However the main opposition The Union for Democracy and Social Progress party, whose leader Felix Tshisekedi is running for president, is not taking part in the march.
The opposition claims that the South Korean machines will be used for massive fraud in the presidential, parliamentary and provincial polls on December 23 in the Democratic Republic of Congo.
The vast central African country has never seen a peaceful transition of power since independence from Belgium in 1960.
Kabila, 47, has been in power since 2001. His second and final elected term in office ended nearly two years ago, but he stayed in office thanks to a caretaker clause in the constitution.
Kabila last month promised at the United Nations the country would hold a credible ballot. But the months before he said he would step aside were marred by brutally repressed protests.
Critics worry Kabila is trying to make sure his favoured successor, Emmanuel Ramazani Shadary, a hardline former interior minister, faces no serious challenger.
Overnight Thursday, police put up barricades on main roads in Kinshasa and began systematically checking all vehicles.
The governor of Kinshasa officially authorised the rally after a meeting with organisers who agreed that the rally would not end in the posh Gombe district, where many government buildings, diplomatic missions and big businesses are located, opposition senator Jacques Djoli told AFP.
Kinshasa police chief Sylvano Kasongo called for an orderly march with "no bloodbath and the objective of zero deaths."
After talks in Johannesburg, delegates from the fragmented opposition announced that they would appoint a joint candidate by November 15.
The electoral commission in January put the number of potential voters at more than 46 million, according to the International Crisis Group.
However, Friday's marchers are also calling on the commission to strike off more than 10 million names from the electoral roll because they were registered without digital fingerprints.