By Ange Aboa and Loucoumane Coulibaly
ABIDJAN (Reuters) - Heavy clashes broke out on Monday in the town of Duekoue, in a cocoa-producing area of western Ivory Coast, between forces loyal to incumbent Laurent Gbagbo and his rival in an election dispute, residents and combatants said.
Duekoue has remained under Gbagbo's control since Ivory Coast's 2002-3 civil war, but rebels who seized the north of the country and now back his rival Alassane Ouattara have pushed toward the town as the country's post-election crisis turns increasingly violent.
The rebels said they had taken Duekoue, lying on a main road in a region that produces around 250,000 tonnes of cocoa a year for the world's top growing nation.
"The town of Duekoue has been under our control since 7 a.m. (0700 GMT). We are conducting search operations throughout," said Lacine Mara, spokesman for pro-Ouattara forces in the west.
Gbagbo's forces confirmed the fighting but said they remained in control of at least part of the town. Several independent witnesses said fighting was still going on.
"Our men have been in combat since about 2 a.m. (0200 GMT) this morning with the rebels, who tried to take the town. We control one part and they control the other," said Yao Yao, operations chief of Gbagbo's Front for the Liberation of the Great West (FLGO) militia.
It was not possible to verify the different accounts but residents said clashes continued in the early afternoon.
A violent dispute over the presidential election last November that was meant to draw a line under Ivory Coast's civil war has instead restarted it, after Gbagbo refused to step down despite U.N.-certified results showing that he lost.
Ouattara has been internationally recognized as president but remains holed up in an Abidjan hotel, protected by a ring of U.N. peacekeepers.
Up to one million Ivorians have now fled fighting in the main city Abidjan alone. Others have been uprooted across the country and around 100,000 from the west have crossed into neighboring Liberia, according to the U.N. refugee agency.
"Combat is still raging here," said Father Cyprien Ahoure, who runs the local Catholic church in Duekoue.
"We're getting more and more stray bullets. Three people have been hit and I really don't know if they'll survive. Nobody is yet in control of the city," he added.
Pro-Ouattara forces have already seized four towns in the west and Gbagbo's forces fear that if they capture enough important towns, they will be able to march south to the port of San Pedro, which ships about half Ivory Coast's cocoa crop.
"The rebels want to take Duekoue and Guiglo so they can easily descend on San Pedro," Yao Yao said. "We won't let them."
The violent stand-off has led to 462 confirmed deaths, according to the U.N. The world body is also investigating allegations that 200 African nationals -- from Mali, Burkina Faso, Senegal, Guinea and Togo -- were killed near Guiglo, some 20 miles to the southwest of Duekoue.
Last week around 15,000 pro-Gbagbo youths turned up at army headquarters to enlist, raising fears that all out civil war is now unavoidable.
Weeks of diplomatic efforts by the African Union (AU) to resolve the crisis have failed, and the AU has simply re-affirmed its position that Ouattara is rightful president.
Ouattara rejected over the weekend the African Union's nomination of Jose Brito, Cape Verde's former foreign minister, as an envoy to negotiate an end to the crisis, arguing he was too close to Gbagbo.
Brito told Reuters late Sunday that he had "no personal interest in the subject, but as an African he wants a solution in Ivory Coast ... it is for the parties to find consensus on the High Representative," he said.
A Reuters reporter in the main city of Abidjan also reported shooting and heavy arms fire Monday, from areas where insurgents seeking to oust Gbagbo are pushing toward the city center.
(Writing by Tim Cocks; editing by David Lewis)