CARACAS, VENEZUELA - The family of a Houston-based Citgo oil executive convicted and ordered to prison in Venezuela alongside five others appealed directly to President Nicolas Maduro on Friday for mercy.

In an open letter, relatives of Jose Pereira, 63, wrote to Maduro that Pereira has a long list of health problems that need medical attention.

They ask for Maduro to free him - and the other five - so they can return home to their families in the United States.

"Our purpose for this letter is not to enter into legal tirades about the case," the letter says. "We only want to implore to your humanitarian and compassionate side."

The letter came a day after the Thanksgiving Day verdict finding all six guilty of corruption charges. They've been held for three years in Venezuela.

In a statement Friday, U.S. Secretary of State Mike Pompeo said, "The United States unequivocally condemns the wrongful convictions of the Citgo 6," and that "these six individuals should be immediately returned to the United States."

The so-called Citgo 6 are employees of Houston-based Citgo refining company, which is owned by Venezuela's state oil company, PDVSA. They had been lured to Venezuela in November 2017 for a business meeting and were arrested.

In addition to Pereira, the others convicted were Gustavo Cardenas, Jorge Toledo, brothers Jose Luis Zambrano and Alirio Zambrano, and Tomeu Vadell - all now U.S. citizens. The judge sentenced them to eight years, 10 months.

They were also charged with financial crimes stemming from a never-executed proposal to refinance some $4 billion in Citgo bonds by offering a 50% stake in the company as collateral. Maduro at the time accused them of "treason." They all pleaded innocence.

Jose Pereira, a permanent U.S. resident, had been promoted to interim Citgo president shortly before the arrest. He received the longest sentence of 13 years.

"We ask solemnly and respectfully that you intercede in our case," they asked Maduro. "So we can achieve freedom for these six men and allow them to return home to their loved ones."

Relatives say the men were wrongly convicted, and the defense lawyers vowed to appeal verdicts.

Venezuela's Supreme Tribunal of Justice announced the verdicts and prison sentences, but officials in Maduro's government have not commented on the trial's outcome.