Alfredo Díaz died in his jail cell at the El Helicoide prison, human rights organisations and opposition groups say

The US has criticised 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, a collection of islands off Venezuela's Caribbean coastline, 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.

He said that Díaz had only been allowed one visit from his daughter during the entire length of his incarceration. He added that 17 political prisoners have died in the country since 2014.

Opposition groups have also criticised 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.

"Sadly, it adds to an alarming and painful chain of deaths of political prisoners detained in the context of the post-election repression," she wrote on X.

Machado, a vocal critic of Maduro's government who was integral to galvanising the opposition against him, will likely be absent from the Nobel Prize-giving ceremony in Oslo on Wednesday. Venezuela's attorney general said last month that she would be considered a "fugitive" if she travelled to Norway.

The Democratic Unitary Platform, an opposition alliance, said Díaz "died unjustly".

Diaz's own political party, Democratic Action (AD), also paid tribute to the former governor, saying he had been unjustly detained without due process and had remained in conditions "that should never have violated his fundamental rights".

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.

US air strikes on vessels in the Caribbean and Pacific have killed more than 80 people.

Trump has accused Maduro of "emptying his prisons and insane asylums" into the US, and designated two Venezuelan drug cartels - Tren de Aragua and Cartel de los Soles - as terrorist organisations, the latter of which Trump alleged Maduro led.

Maduro has in turn accused the US of using its war on drugs as an excuse to depose his socialist government and get its hands on Venezuela's vast oil reserves. Colombia's left-wing President Gustavo Petro has said the US strikes were an attempt to "dominate" Latin America.

The US has also stationed a large naval force - its largest deployment in the region in decades - along with thousands of troops.

The Venezuelan army reportedly swore in more than 5,600 soldiers in one go on Saturday, in response to what military leaders called US "threats".

The same day, the Venezuelan government said that Maduro and Turkish President Recep Tayyip Erdogan had agreed to resume Turkish Airlines flights between the two nations.

The carrier was one of six major international airlines to have their landing licences revoked after temporarily suspending flights to Caracas over a US warning of "heightened military activity" in the area. (BBC)

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