Lieutenant Ascanio Tarascio and Sergeant Estiben Zarate were tried in a civil court in Caracas, where they were sentenced to six years and eight months in prison for manslaughter, Alonso Medina Roa said.

Roa, who represented the late naval officer Rafael Acosta, was disappointed that the judge had not kept the main charge of torture, which carries a sentence of 15 to 25 years in prison for state agents, according to the criminal code.

Tarascio and Zarate were placed in preventive detention on July 1, after Acosta's death at the end of June.

Acosta was part of a group of 13 people arrested for alleged involvement in a failed "coup d'etat" against Maduro, which the government has tied to opposition leader Juan Guaido.

Maduro's government has claimed the coup was to have taken place on June 23 and 24 and would have involved the assassination of the president and several other senior officials.

Acosta was detained on June 21, and his whereabouts were unknown before he was brought before a military tribunal a week later.

According to his lawyer, the naval officer appeared in court in a wheelchair, unable to speak and showing signs of having been tortured.

The judge sent him to a military hospital where he died the next day.

UN rights chief Michelle Bachelet said she was "shocked" by Acosta's death, adding weight to claims by the United States and Venezuelan opposition that he may have been tortured.