( CNN ) -- The runner-up in Honduras ' presidential election says she will not recognize the outcome and is demanding a vote-by-vote recount . The strong allegations of fraud by Xiomara Castro , the wife of ousted former President Manuel Zelaya , raise the possibility of political unrest in the Central American country . The leftist candidate says her political party has uncovered evidence of fraud and vows to challenge the triumph of ruling party candidate Juan Orlando Hernandez . With 80 % of votes counted , electoral officials declared Hernandez the winner with more than 35 % of the vote , placing him six percentage points ahead of Castro . Castro had been mostly quiet since election night . Friday was her first public appearance since the vote . `` I am here , once again before you , to reiterate that we have found countless evidence of the disgusting monstrosity with which they are robbing the presidency from our people , '' she said . International election observers have said there were some irregularities , but in general agreed that the elections were transparent . The U.S. State Department noted that the Organization of American States and European Union observers reported a clean election . `` We support the ongoing work of ( electoral officials ) and the political parties to finalize the results and resolve inconsistencies in a transparent manner and urge the Honduran people to continue to demonstrate their respect for rule of law and peaceful , democratic processes , '' State Department spokeswoman Jen Psaki said . Castro said she would not back down from her challenge and accused the ruling party of rigging the system to help their candidate . `` We reject the legitimacy of any government that is the product of this suffocating assault , '' she said . Following her husband 's ouster in a 2009 coup , Castro founded the Liberty and Refoundation Party ( LIBRE ) on a platform that carried on her husband 's projects and found herself at the top of some polls . A victory by Castro would have been a remarkable comeback for Zelaya back to the presidential palace , even as a first husband .
Electoral officials declared ruling party candidate Juan Hernandez elected . But opposition candidate Xiomara Castro alleges fraud . She demanded a full recount to check for irregularities .