General Raul Baduel, who aligned with Venezuela's late Hugo Chavez but later broke ranks with the socialist strongman and spent years as a prominent political prisoner, died of Covid-19, according to an official announcement earlier this week.

"We are deeply saddened by Raul Baduel's death in detention. We call on #Venezuela to ensure an independent investigation," the Office of the UN High Commissioner for Human Rights said on Twitter.

The office also asked that Venezuelan detainees be afforded access to healthcare and called on the government to release those who were arbitrarily detained.

Baduel's daughter Andreina Baduel accused President Nicolas Maduro's regime of having "assassinated" her father, adding on Twitter that "it was untrue that he had Covid-19."

Baduel served as defense minister under Chavez and helped reinstate him after the April 2002 coup that briefly removed him from power.

But the two later fell out after Baduel argued against a constitutional reform proposed by Chavez.

In 2009, Baduel was accused of corruption and jailed for eight years.

Freed in 2015, Baduel was arrested again in 2017 and accused of plotting against Maduro.

Two of Baduel's sons have also been arrested over alleged conspiracy.

Raul Emilio Baduel has since been freed but Josnars Adolfo Baduel remains in detention, accused of taking part in the failed maritime invasion in May 2020 known as "Operation Gideon" that was aimed at overthrowing Maduro.

Gonzalo Himiob, a lawyer with Foro Penal, a human rights organization that provides legal aid, said that Baduel was the 10th political prisoner to die in custody since 2015.