Venezuela's President Nicolas Maduro and seven other candidates for July elections on Thursday signed an agreement to respect the results, although the country's main opposition abstained, saying the government had already breached an existing deal.
The nine-point agreement was presented by the National Electoral Council (CNE), Venezuela's highest electoral authority which critics say is an extension of the ruling party.
Main opposition candidate Edmundo Gonzalez abstained from signing, as did Enrique Marquez.
In a statement released on Thursday, Gonzalez said the opposition had complied with prior conditions for elections established in an agreement signed between the government and the opposition in Barbados last year.
"This agreement has been violated by one of the parties, who rescinded an invitation to international observers from the European Union and increased persecution of leaders and supporters of our campaign," Gonzalez said in the statement.
CNE President Elvis Amoroso said Gonzalez "did not respond to the call of the homeland" after calling him forward to sign, while the official television station broadcast an empty chair.
Gonzalez, a 74-year-old former diplomat who leads the polls, told reporters early on Thursday that he had not received any summons from the CNE.
After signing the document, Maduro said the act showed that "we do not want violence (...) we believe the electoral authority."
"I call on all Venezuelans to respect this document and to support the National Electoral Council, may its word be sacred," Maduro said.
