By Ange Aboa and Loucoumane Coulibaly
ABIDJAN (Reuters) - Heavy clashes broke out on Monday in the town of Duekoue, in 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 in a region that produces around 250,000 tons of cocoa a year for the world's top grower.
"The town of Duekoue has been under our control since 7 a.m. (0700 GMT). We are conducting search operations throughout," said Lacine Mara, a 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.
"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.
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.
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.
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. 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.
"Since this morning, the military and the militias have been fighting with the rebels, who have taken control of the main road leading to (rebel-held) Man," said cocoa trader Daouda Fadika. "We're hearing heavy weapons fire and Kalashnikovs."
A Reuters reporter in the main city of Abidjan also reported shooting and heavy arms fire on Monday, from areas where insurgents seeking to oust Gbagbo are pushing toward the city center.
Ouattara has been internationally recognized as president but remains holed up in an Abidjan hotel, protected by a ring of U.N. peacekeepers.
(Writing by Tim Cocks; editing by David Lewis and Giles Elgood)