Venezuela on Saturday freed seven Americans jailed in the South American country in exchange for the release of two nephews of President Nicolas Maduro’s wife, who had been jailed by the United States for years on drug-smuggling charges, a senior US official said.

The exchange of Americans, including five oil executives who have been held for nearly five years, is an exchange the largest trade in detained citizens ever conducted by the Biden administration.

“It is with relief and joy that we welcome back into our families today the seven Americans who have been unlawfully detained in Venezuela for far too long,” said Joshua Geltzer, deputy national security adviser.

It is a rare gesture of goodwill from Maduro as the Socialist leader seeks to restore relations with the United States after defeating most of his domestic opponents. The deal is as follows months of rear diplomacy Washington’s chief hostage negotiator and other US officials are holding secret talks with a major oil producer that have gained momentum after sanctions against Russia put pressure on global energy prices.

Among those released are five Houston-based Citgo employees — Tome Waddell, Jose Luis Zambrano, Alirio Zambrano, Jorge Toledo and Jose Pereira — who were lured to Venezuela before Thanksgiving in 2017 to attend a meeting at the parent company’s headquarters in the state – oil giant PDVSA. Once there, they were taken away by masked security agents who stormed the Caracas conference hall.

He was also released Matthew Heatha former US Marine corporal from Tennessee who was arrested in 2020 at a roadblock in Venezuela on what the State Department called “spectacular” weapons charges, and Florida resident Osman Khan, who was arrested in January.

The United States released Franky Flores and his cousin Efrain Campo, nephews of the “first fighter” Cilia Flores, as Maduro called his wife. The men were arrested in Haiti as part of a 2015 drug bust and immediately brought to New York for trial. The following year, they were convicted in a highly charged case that dealt harshly with US allegations of drug trafficking at the highest levels of the Maduro administration.

Both were pardoned by President Joe Biden before their release.

The Biden administration has been under pressure to do more to bring home about 60 Americans it believes are being held hostage overseas or illegally detained by hostile foreign governments. While much of the focus is on Russia, where the US has so far tried unsuccessfully to secure the release of WNBA star Brittney Griner and another American, Paul Whelan, Venezuela holds the largest contingent of Americans suspected of being used as bargaining chips.

At least four more Americans remain in custody in Venezuela, including two former Green Berets were involved in a violent bid to oust Maduro in 2019, and two other men who, like Khan, were detained for allegedly entering the country illegally from neighboring Colombia.

Earlier this month, the family of Los Angeles attorney Avin Hernandez told CBS News that a 44-year-old man took a trip to Colombia in April and did not return. They said he and a friend went to the Colombian-Venezuelan border to get a passport stamped, but things went wrong and the two were detained.

Both were charged with conspiracy and conspiracy to commit crimes against the state, and Hernandez’s brother told CBS News that he has had little contact with his family since he was imprisoned.

The Biden administration has not released another prisoner long sought by Maduro: Alex Saab, a businessman insider who Venezuela says is a diplomat and US prosecutors say facilitates the corrupt regime. Saab fought extradition from Cape Verde, where he was arrested last year during a stopover on his way to Iran, and is now awaiting trial in Miami federal court on charges of siphoning off millions in government contracts.

The oil company’s executives were found guilty of embezzlement last year in a trial marred by delays and irregularities. They were sentenced to eight to 13 years in prison for a failed offer to refinance the oil company’s billion-dollar bonds. At the time, Maduro accused them of “treason,” and Venezuela’s Supreme Court upheld their lengthy sentences earlier this year.

The men have all pleaded not guilty, and the State Department has deemed them — and the two other Americans released Saturday — illegally detained.

Earlier this year, two American citizens who were considered unjustly detained by the United States, were released from a Venezuelan prison. Gustavo Cardenas, one of the detained Citgo executives, and tourist Jorge Fernandez returned to the United States in early March.