One of President Nicolás Maduro's closest aides has been extradited from Cape Verde to the United States, where he's been charged with money laundering.
The US Treasury says Alex Saab worked as a front man for Maduro's regime, reports BBC.
The talks were to resolve a political crisis that has led to violence and the collapse of the economy.
The discussions had been due to resume this weekend in Mexico.
The US Treasury accuses Saab - a Colombian-born businessman and Venezuelan envoy - of using his accounts in American banks to launder the proceeds of corruption.
The Venezuelan government has accused the US of kidnapping diplomatic personnel and announced the suspension in negotiations with the opposition that were set to resume this weekend.
Saab was due to be a member of the government's negotiating team in talks with the opposition in Mexico.
Venezuela has faced chronic shortages of food and medicine as a result of years of political and economic crisis.
Venezuela's opposition has described Mr Saab as a front man doing shady deals for the populist socialist regime of Mr Maduro.