Rolling out tanks, missiles and 100,000 men, Venezuela launched 10 days of military exercises Saturday, amid sky-high tensions over US sanctions slapped on officials accused of an opposition crackdown.

President Nicolas Maduro's socialist, Cuban-allied government -- struggling with sliding oil prices, the region's highest inflation, desperate shortages and rising discontent -- threw the spotlight on its Chinese amphibious tanks, Russian-built missiles and other military hardware.

"Congratulations to the Bolivarian National Armed Forces, and to the people, for the joint exercises," tweeted Maduro, who in two years time has alleged over a dozen coup bids against him and his government by the United States or local opposition members.

"Civilian-military union to keep having a Fatherland," Maduro added. "And may our sacred fatherland never have a (US) imperial boot set foot on it. Long live Venezuela!"

- Civilian-military union emphasis -

The nationwide exercises, covered for hours on end on local television, will last 10 days and enlist the participation of 20,000 civilians, in addition to government troops in the South American OPEC member with the world's largest crude reserves, officials said.

The maneuvers come at a time of heightened tensions with the United States, which Venezuela has labeled an imperial brute since the time of Maduro's late mentor, longtime president Hugo Chavez.

Both elected socialists, they have been harsh critics of the United States, which they slam for failing to cooperate with leftists when they win democratically-held elections.

But critics note that the government under Chavez and Maduro has acted to curb dissent in the legislature and on the streets.

And Venezuela, closely allied with communist Cuba, is now experiencing severe shortages of even the most basic needs, such as milk, toilet paper or diapers.

Maduro recently accused Washington of backing an opposition plot to overthrow him in a coup that would have involved bombing the presidential palace. The US government has dismissed the charges as baseless.

In April 2002, when Chavez was briefly ousted for two days, the United States did not come to his aid but instead threw its support behind an adversary, in a move that cost the US much credibility in the country.

Relations hit a new low on Monday, when US President Barack Obama slapped new sanctions on the regime, calling Venezuela "an extraordinary threat to the national security" of the United States.

- How does Venezuela threaten US? -

Caracas responded by angrily recalling its envoy to Washington and ramping up its military preparedness.

The South American bloc UNASUR labeled Obama's executive order an "interventionist threat," with Ecuadoran Foreign Minister Ricardo Patino saying it "violates Venezuela's sovereignty."

Despite the frosty ties, the United States is still the biggest consumer of Venezuela's oil.

Venezuelan Defense Minister General Vladimir Padrino Lopez said that the military maneuvers, many of which were to be held in the south of Caracas, were meant to prepare soldiers for "their mission, their goal and with the will to be victorious."

Other exercises in the show of might focus on Venezuela's oil-producing areas, including the Caribbean coast and an oil field some 200 kilometers (125 miles) to the west of Caracas.

Military officials said they will also test the nation's air defenses and will ensure that its anti-aircraft systems are ready to be deployed if needed.

Interviewed on television about the exercises, the officials echoed Maduro's line that the "civilian-military union" was defeating "imperialists," "people who have no fatherland" and "invaders."

Now Maduro is seeking extraordinary powers from the legislature that would allow him to rule by decree.

His popularity has sunk in the past year amid the economic crisis.

Elected to succeed his late mentor Hugo Chavez in April 2013, Maduro had obtained yearlong powers to impose economic laws by decree.