Venezuela has released a group of former executives of U.S.-based refining company Citgo on house arrest, a source familiar with the situation said on Friday, three years after they were arrested on corruption charges. The officials were detained in November 2017 after being called into a meeting at the Caracas office of state oil company PDVSA, which owns Citgo. A Venezuelan court in November sentenced the six former executives, who were accused of crimes such as embezzlement, money laundering and conspiracy, to prison terms ranging from eight to 13 years. Venezuela"s information ministry did not immediately reply to a request for comment. The executives - Jose Pereira, Jose Luis Zambrano, Alirio Jose Zambrano, Jorge Toledo, Tomeu Vadell and Gustavo Cardenas - all denied the charges. The U.S. State Department called the trial a "kangaroo court" and described their detentions as unlawful. The United States labels Maduro a dictator who rigged his 2018 re-election and uses the justice system to stifle dissent. Maduro says Washington wants to control Venezuela"s oil reserves and aims to oust him in a coup.