Venezuela’s military on Saturday held exercises that deployed civilian militia and armored vehicles in the capital Caracas and around the country, an effort by President Nicolas Maduro to show strength as Washington prepares to escalate sanctions.

Maduro accuses the United States of preparing an invasion of the OPEC nation, which in 2017 United States (US) President Donald Trump described as a possibility. Since last year the United States has ramped up economic sanctions against his 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.

“We have proven the level of command and control of the Bolivarian militia, complemented by the National Bolivarian Armed Forces,” said Defense Minister Vladimir Padrino in statements broadcast on state television.

In one exercise seen by Reuters along a highway in eastern Caracas, a group of several hundred people including 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 armored vehicles.

The “invaders” were represented by a group of cars that blocked the highway.