The US has criticized the Venezuelan government over the death of an opposition figure in custody, calling it a reminder of the vile nature of President Nicolás Maduro's regime.
Alfredo Díaz died in his prison cell at the El Helicoide prison in Caracas where he was being held for more than a year, human rights organisations and opposition groups have said.
The Venezuelan government said the 56-year-old showed signs of a heart attack and was taken to hospital, where he died on Saturday.
The US intervention is the latest in an escalating war of words between the Trump administration and Maduro, who has accused it of seeking regime change.
In recent months, the US has increased its military presence in the region and has carried out a series of deadly strikes on boats it says have been used for smuggling drugs.
US President Donald Trump has accused Maduro himself of being the head of one of the region's drug cartels - an allegation the Venezuelan president vehemently denies - and threatened military action by land.
The US State Department's Bureau of Western Hemisphere Affairs said Díaz had been arbitrarily detained in a torture centre.
Díaz was detained in 2024 after being among many opposition figures to dispute the results of that year's presidential election.
Venezuela's government-controlled election council declared Maduro the winner, despite opposition tallies showing their candidate had won by a landslide.
The elections were widely dismissed on the international stage as neither free nor fair, and sparked protests across the country.
Díaz, the former governor of the Nueva Esparta state, was accused of incitement to hatred and terrorism for questioning Maduro's claim to victory.
The Venezuelan human rights group Foro Penal has raised concerns over deteriorating conditions for political prisoners in the Latin American nation.
Another political prisoner has died in Venezuelan jails. He had been imprisoned for a year, in solitary confinement, Alfredo Romero, the organisation's president, wrote on X.
Opposition groups have also criticized the government over the death of Diaz.
María Corina Machado, a prominent opposition leader who won this year's Nobel Peace Prize but who remains in hiding to avoid arrest, said Díaz's death was not an isolated incident.
Machado has been integral to galvanising the opposition against Maduro, despite facing risks for her activism.
Tensions between the US and Venezuela have become increasingly strained over what Trump has described as efforts to stem the flow of drugs and migrants into the US.
Trump has accused Maduro of emptying his prisons and insane asylums into the US, escalating military coordination against alleged drug cartel activities linked to the Venezuelan government.
The implications of Díaz's death and the political climate in Venezuela hint at the ongoing struggle for human rights and democracy within the nation, drawing international scrutiny.
