Caracas (AFP) - Two Americans, including a former executive of oil giant Citgo, were released from prison in Venezuela Tuesday, just days after a high-level US delegation met with President Nicolas Maduro.

The Citgo executive, Gustavo Cardenas, is one of the so-called "Citgo 6" -- five Venezuela-born American citizens and one with US permanent residency -- who have been held in Venezuela since 2017, accused of corruption.

All six executives were handed lengthy jail sentences, and Washington has repeatedly asked for their release, with State Department spokesman Ned Price saying last October that they were being held as "political pawns."

Attorney Jesus Loreto said that "the other five are still detained."

Citgo is the US subsidiary of Venezuela's state oil company PDVSA.

US President Joe Biden confirmed the release of Cardenas and the second American, Jorge Alberto Fernandez, saying they were "were wrongfully detained in Venezuela."

"We also remember the names and the stories of every American who is being unjustly held against their will -- in Venezuela, in Russia, in Afghanistan, Syria, China, Iran, and elsewhere around the world," Biden said in a statement.

Fernandez, a Cuban-American, was arrested in 2021 in Tachira state, bordering Colombia, after being accused of terrorism.

The NGO Coalition for Human Rights and Democracy tweeted that Fernandez "was unjustly detained... and accused of being a terrorist, simply for carrying a drone."

'Two beautiful flags'

The US delegation that traveled to Caracas at the weekend discussed energy supplies with Maduro, as Washington looks for ways to replace Russian oil imports, which have now been banned over Moscow's invasion of Ukraine.

The meeting was seen as a possible turning point in relations, since the United States ended its Venezuelan embassy operations in 2019, after Maduro claimed victory in a 2018 election that many countries deemed illegitimate.

Along with more than 50 countries, the United States recognized opposition leader Juan Guaido as interim president and imposed a battery of sanctions seeking to displace the socialist ruler, including an embargo on oil imports.

The US Justice Department has also accused Maduro of drug trafficking and has even offered a $15 million reward for information leading to his capture.

Nonetheless, according to Maduro, the delegation held a "respectful, cordial and diplomatic" meeting for almost two hours over the weekend.

"We did it in the presidential office," Maduro said on Monday in a television address. "There were the two beautiful flags, united as the flags of the United States and Venezuela should be."

While Maduro did not say what topics were addressed, White House press secretary Jen Psaki confirmed that "energy security" was one of the issues raised.

More Americans behind bars

It is not yet clear whether Cardenas and Fernandez have been cleared of their charges or by what process they were released.

Last month, Venezuela's Supreme Court confirmed sentences for the "Citgo 6," including one for Cardenas of eight years and 10 months.

Former Citgo president Jose Pereira, who has been convicted of embezzlement, was sentenced to 13 years and seven months, and ordered to pay a fine of $2 million.

The remaining former executives -- Tomeu Vadell, Jorge Toledo, Jose Luis Zambrano and Alirio Zambrano -- received the same sentence as Cardenas.

The United States has also demanded the release of Matthew Heath, a former Marine who was arrested in September 2020 for "terrorism," as well as Airan Berry and Luke Denman, two veterans accused of a failed sea raid seeking to overthrow Maduro in May 2020.