Venezuela hurtled toward a high-stakes political confrontation with the opposition calling a general strike Wednesday in a bid to stop embattled President Nicolas Maduro from going ahead with a controversial plan to rewrite the country's constitution.

Even before the two-day strike began, a prominent opposition leader, Leopoldo Lopez, made a direct appeal to the military early Wednesday to withdraw its support from the plan he called a "constitutional fraud" aimed at eliminating democratic rule.

The military, along with the courts, has proved to be a key pillar of support for Maduro through months of deadly street protests and an economic collapse that has led to widespread shortages and public anger.

On Sunday, things between the two sides are expected to come to a head.

That's when Maduro is to hold a controversial election to choose 545 members for a body, called the Constituent Assembly, tasked with rewriting the constitution drafted under his late predecessor Hugo Chavez.

The vote has been strongly criticized inside Venezuela and internationally, particularly among heavyweight Latin American states such as Brazil and Mexico.

US President Donald Trump has threatened unspecified economic sanctions if it goes ahead.

Lopez, who is under house arrest after spending nearly three and a half years in a military prison, urged the military to withdraw its support for Sunday's elections.

"I invite you to not be accomplices to the annihilation of the republic, to a constitutional fraud, to repression," Lopez said in a video posted on Twitter.

The opposition-controlled National Assembly, meanwhile, has challenged the government by appointing 33 supreme court judges to rival ones loyal to Maduro.

- Judges arrested -

Maduro, though, has shown no sign of backing down.

On Tuesday, Venezuelan intelligence officials arrested two of the opposition-appointed judges, bringing to three the number being detained.

Maduro has vowed that the opposition's judges would be arrested "one by one" and their assets frozen.

The opposition, which organized an unofficial referendum against the constitutional revision in which a third of the electorate rejected Maduro's plan, has called for a boycott of Sunday's vote.

The president's attorney general, Luisa Ortega, has also broken ranks with him over the Constituent Assembly and become a vociferous opponent.

Meanwhile, street protests against Maduro continue. In four months, more than 100 people have died during the demonstrations.

- Shrinking economy -

The Venezuelan government is also being squeezed by the economic crisis in the country, where food and medicine have become scarce.

The oil export-dependent economy is shrinking 12 percent this year, after a contraction of 18 percent last year, according to the latest forecast from the International Monetary Fund.

Inflation is projected to top 720 percent.

Venezuela's currency reserves have dwindled to under $10 billion as the government has kept up debt repayments at the expense of imports, to stave off a crippling default.

"That is not going to happen," Maduro pledged last week. "Venezuela is meeting its international commitments and will continue to do so."

Instead, the leader has blamed a conspiracy between the rightwing opposition and the United States to wage an "economic war" on his government in an attempt to topple him.

"The US right wing thinks it can give orders in Venezuela, but the only one who gives orders in Venezuela is the people," Maduro said on his weekly broadcast.

Maduro has presented his Constituent Assembly as the only path to peace and prosperity. But he has not explained how the body or a new constitution would bring that about.

Surveys by Datanalisis, a polling firm, have shown that more than 70 percent of Venezuelans reject Maduro's leadership.

source: AFP