WASHINGTON/CARACAS - A U.S. delegation led by President Joe Biden's chief hostage negotiator ended a visit to Venezuela on Thursday after failing to secure the release of any of the Americans detained there, U.S. officials said.

Hostage affairs envoy Roger Carstens was part of a group that met Venezuelan officials this week to press for the handover of prisoners and coax President Nicolas Maduro's government to restart stalled negotiations with the country's opposition, according to people familiar with the matter.

Carstens and U.S. Ambassador to Venezuela James Story were especially focused on the case of Matthew Heath, a U.S. Marine veteran hospitalized following what his family said was a suicide attempt last week after nearly two years of imprisonment.

The U.S. officials were allowed to visit Heath in a Venezuela military hospital, the sources said.

Heath is one of at least eight Americans known to be held in Venezuela, including five executives of Citgo Petroleum, a U.S.-based unit of Venezuela's state oil company PDVSA.

Though the visit did not lead to releases, it was the latest sign of tenuous re-engagement after years of hostilities between the United States and OPEC member Venezuela, amid Russia's war against Ukraine that has hit global oil supplies.

Talks this week did not include Venezuela's oil sector, under U.S. sanctions since 2019, according to sources familiar with the matter.

A State Department spokesperson confirmed Carstens and Story's departure. "The trip focused on discussions about the welfare and safety of wrongfully detained U.S. nationals in Venezuela and to press for their release," the spokesperson said, adding Carstens saw detainees to "assess their well-being."

A statement issued by Heath's aunt, Trudy Rutherford, on behalf of his family said that despite Carstens' "best efforts," the U.S. delegation "was not able to secure an emergency medical evacuation for Matthew."

Heath was arrested in 2020 on terrorism charges, which he denied. U.S. officials said Heath was not sent by Washington and accused Venezuela of holding him on trumped-up charges.

In March, a White House-led delegation, including Carstens, met Venezuelan President Nicolas Maduro, and a potential easing of U.S. sanctions was among the topics discussed.

Venezuela soon freed two Americans - a former Citgo executive and a Cuban American - and promised to resume talks in Mexico with the opposition. Maduro has yet to agree on a date to return to the negotiating table.

But since the March visit, the Biden administration has taken a few steps to slightly soften its Venezuela policy.

Republican lawmakers and some of Biden's fellow Democrats have criticized the U.S. approach as too conciliatory toward Maduro.

  - Reuters