Two of Venezuela's leading opposition parties will boycott upcoming political races to protest recent gubernatorial elections that they say were rigged to favor President Nicolas Maduro's ruling party.

National Assembly President Julio Borges announced Monday that his Justice First party will run no candidates in mayoral elections across the country in December.

The Popular Will party also announced a boycott.

They are among nearly 30 parties that make up Venezuela's fractured opposition.

Borges says that instead they will fight for elections free of fraud and deceptive tactics.

Maduro's socialist party unexpectedly won nearly all the gubernatorial elections earlier this month in voting that the opposition disputed as rigged.

Building on its momentum, the pro-government constitutional assembly next called for the mayoral races to be held by year's end.