Venezuela's President Nicolas Maduro speaks during a ceremony to mark the 17th anniversary of the return to power of Venezuela's late President Hugo Chavez in Caracas, Venezuela April 13, 2019.

The U.S., European Union and other countries around the world have accused Venezuela's government of torturing and murdering a Navy captain held over an alleged plot to assassinate President Nicolas Maduro.

Rafael Acosta Arevalo, a 49-year-old navy captain, died in the early hours of Saturday morning after being rushed to a hospital in the capital city of Caracas, the South American country's defense ministry said in a statement.

He appeared in court on Friday but fainted before proceedings could begin.

Acosta was detained on June 21 and charged with treason and conspiring to rebel. He denied the charges.

Venezuela's government has said it will investigate Acosta's death, but has not elaborated on the cause or circumstances preceding it.

"No one, absolutely no one can remain indifferent to this horror, let alone the men and women of the armed forces," Guaido said via Twitter over the weekend.

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"It is up to us to be united to put an end to a dictatorship that tortures and murders," he said in another tweet.

The Lima Group, which is comprised of 11 Latin American countries and Canada, reportedly said that Acosta exhibited "visible signs of torture" when he was brought before a military tribunal on Friday.

His death comes a week after United Nations human rights chief Michelle Bachelet visited Venezuela to investigate allegations that Maduro's security forces had tortured and killed members of the opposition.