The United States warned Tuesday it was ready to snap back sanctions on Venezuela's vital oil industry unless opponents of President Nicolas Maduro are allowed to run against him, as the leftist government vowed to hit back through migration.
The sharp exchanges came just two months after the adversaries took tentative steps to improve relations following a deal between Maduro and the opposition.
But that deal has since collapsed with the barring of credible rivals from competing in this year's presidential elections.
The United States announced it was immediately winding down a license that allowed operations by the Venezuelan state-owned gold mining company, Minerven.
The State Department said it was also ready to reimpose sanctions on dealings with the oil and gas sector, Venezuela's key money-maker, but gave a deadline of April 18 for progress between Maduro and the opposition.
"There is still time for the Maduro regime to change course. There is still time for them to allow a free and fair election," State Department spokesman Matthew Miller told reporters.
"We are hopeful that that's what they'll do, but if they don't, we're prepared to implement our sanctions," he said.
Miller said that Maduro needed to abide by the agreement with the opposition, reached in October in Barbados, and allow other candidates to "freely participate" in the election.
Venezuela's Supreme Court, loyal to Maduro, on Friday upheld a 15-year ban on holding public office against the president's main opponent in elections due this year, Maria Corina Machado.
The court also confirmed the ineligibility of a possible opposition stand-in -- two-time presidential candidate Henrique Capriles.
Machado, after the court decision, accused Maduro and his "criminal system" of seeking "fraudulent elections."
- Threat on migration -
Venezuelan authorities responded by threatening to hit Biden in a sensitive area ahead of his own bid for reelection -- migration.
More than seven million Venezuelans have fled over the past decade as the economy implodes, and a growing number have sought to enter the United States.
Vice President Delcy Rodriguez warned that Venezuela on February 13 will cancel repatriation flights for its nationals -- which started in October in an initial deal between the Maduro and Biden administrations -- if the United States goes ahead with "intensifying the economic aggression."
"All of Venezuela rejects the rude and improper blackmail and ultimatum expressed by the US government," Rodriguez wrote on X.
In early 2019, the United States declared Maduro to be illegitimate after concerns about a previous election, with most Western and Latin American countries switching recognition to then opposition leader Juan Guaido.
But years of sanctions and other pressure failed to dislodge Maduro, who enjoys support from a political patronage system, the military and Cuba, Russia and China.
The Biden administration, after initially keeping the sanctions approach of his predecessor Donald Trump, shifted gears.
In November Washington gave a green light to Chevron to operate in Venezuela and, just before Christmas, Venezuela freed 10 detained Americans in a swap with the United States which released a Maduro confidante.
Asked whether the Biden approach had failed, Miller pointed to the Americans' release, saying the United States had already achieved "a very important goal."
US officials have privately acknowledged that they saw limited prospects for Maduro to allow a vote in which he could lose power, but believed it was worth trying.
Maduro last week made claims of plans to assassinate him and said the Barbados agreements are "mortally wounded."
Trump's Republican Party has attacked Biden's dealings with Maduro, but leading members of the president's Democratic Party also called for a return of sanctions after the disqualification of candidates.