TEGUCIGALPA Leftist Honduran presidential candidate Xiomara Castro refuses to accept partial official results that show her conservative rival on course to win Sunday's election, setting the stage on Monday for a drawn-out conflict.
Castro, the wife of deposed leader Manuel Zelaya, and her team said early Monday that an exit poll drawn up for her party showed she was winning. They claimed fraud and accused the electoral authority of manipulating the result.
A partial count issued by the electoral authority on Sunday gave National Party candidate Juan Hernandez some 34.3 percent support while Xiomara Castro had nearly 28.7 percent.
The preliminary tally was based on a count from 54.5 percent of polling booths. The next update is due after midday Monday.
"We don't accept this result ... They can't do this to us, they are stealing the election," Zelaya told reporters. "We do not use violence, weapons, but we know how to defend our rights."
Manuel Zelaya was ousted in a 2009 coup after his opponents accused him of trying to seek re-election, which is banned under the constitution. The debacle plunged Honduras into a deep political crisis and widened tensions between the left and the right in Latin America.
The deposed leader had hoped to stage a comeback behind his wife if she reached presidential office.
Honduras was a key ally of the United States during Central American civil wars in Nicaragua, El Salvador and Guatemala, and is the region's No.1 coffee exporter.
"The result is being manipulated by the electoral tribunal to portray a reality we don't accept," Enrique Reina, Castro's running mate, told Reuters late on Sunday.
However, the U.S. ambassador to Honduras and the head of the European Union's election observers said the voting process was clean and urged the participants to respect the results.
Hernandez said Mauricio Villeda, the Liberal Party candidate lying a distant third who also initially challenged the partial count, had called to congratulate him.
Castro was first to claim victory on Sunday, citing an exit poll drawn up for her own party and telling cheering supporters: "I am the president."
Then the electoral authority published preliminary official results showing she was trailing Hernandez - indicating the possible continuity of outgoing President Porfirio Lobo's right-leaning economic policies.
Hernandez posted a photograph on Twitter late on Sunday of himself and supporters praying on their knees. "Thanks to my God, and thanks to the people of Honduras for this triumph," he wrote.
He has vowed a tough militarized response to drug gang violence that has earned Honduras the dubious distinction of having the world's highest murder rate, or more than 85 killings per 100,000 people.
(Additional reporting by Miguel Gutierrez; Writing by Simon Gardner; Editing by Philip Barbara)