Venezuela's military has deployed civilian militia and armoured vehicles in the capital Caracas and around the country, in an effort by President Nicolas Maduro to show strength as Washington prepares to escalate sanctions.
Maduro accuses the United States of preparing for an invasion of the country, which US President Donald Trump described as a possibility, in 2017.
Since last year the United States has ramped up economic sanctions against the Maduro government.
The exercises were launched days after Maduro formally incorporated the civilian reserve, a group of some 4 million volunteers with limited military training, into the armed forces alongside the army, navy, air force and National Guard.
In one exercise along a highway in eastern Caracas, several hundred soldiers and militia members participated in a 10-minute drill that involved blocking "invaders" from entering the capital.
They were joined by civilian members of the ruling Socialist Party dressed in red shirts who served as look-outs, while soldiers drove armoured vehicles.
Maduro's adversaries dismiss such exercises as theatrics meant to disguise the decay of the armed forces amid hyperinflation that has made Venezuelan salaries - including those of soldiers - insufficient to buy basic food.
"It's a propaganda exercise by the dictatorship today," opposition leader Juan Guaido said in a press conference.
"I say to the armed forces ... we are with you, we know about those malnourished soldiers."
The United States has implemented a broad sanctions program against the Maduro government and has urged the armed forces to turn against him.
Australian Associated Press