The Venezuelan army swore in 5,600 soldiers on Saturday, as the United States cranks up military pressure on the oil-producing country.
President Nicolas Maduro has called for stepped-up military recruitment after the United States deployed a fleet of warships and the world's largest aircraft carrier to the Caribbean under the pretext of combating drug trafficking.
American forces have carried out deadly strikes on more than 20 vessels, killing at least 87.
Washington has accused Maduro of leading the alleged "Cartel of the Suns", which it declared a terrorist organization last month.
Maduro asserts the American deployment aims to overthrow him and seize the country's oil reserves.
"Under no circumstances will we allow an invasion by an imperialist force," Colonel Gabriel Rendon said Saturday during a ceremony at Fuerte Tiuna, Venezuela's largest military complex, in Caracas.
According to official figures, Venezuela has around 200,000 troops and an additional 200,000 police officers.
A former opposition governor died in prison on Saturday where he had been detained on charges of terrorism and incitement, a rights group said.
Alfredo Diaz was at least the sixth opposition member to die in prison since November 2024.
They had been arrested following protests sparked by last July's disputed election, when Maduro claimed a third term despite accusations of fraud.
The protests resulted in 28 deaths and around 2,400 arrests, with nearly 2,000 people released since then.
Diaz, governor of Nueva Esparta from 2017 to 2021, "had been imprisoned and held in isolation for a year; only one visit from his daughter was allowed," said Alfredo Romero, director of the NGO Foro Penal, which defends political prisoners.
The group says there are at least 887 political prisoners in Venezuela.
Opposition leader and Nobel Peace Prize laureate Maria Corina Machado condemned the deaths of political prisoners in Venezuela during "post-electoral repression."
"The circumstances of these deaths -- which include denial of medical care, inhumane conditions, isolation, torture, cruel, inhuman and degrading treatment -- reveal a sustained pattern of state repression," Machado said in a joint statement with Edmundo Gonzalez Urrutia, the opposition candidate she believes won the election.