The Biden administration will allow a six-month suspension of energy-related sanctions to expire in April if Maria Corina Machado and other opposition figures are not allowed to compete against President Nicolas Maduro, the official said, on condition of anonymity.

Venezuela's Supreme Court on Friday kept in place a ban barring Machado from registering for elections scheduled in the second half of this year. The judges upheld findings that she had supported U.S. sanctions, been involved in corruption and lost money associated with Venezuela's foreign assets.

The United States had granted sanctions relief for OPEC member Venezuela in October as part of an electoral deal. But that relief was conditioned on Maduro freeing certain opposition-linked and American prisoners and making progress toward removing bans on a number of opposition figures.

Venezuela in December carried out a prisoner swap that appeared to be a step towards complying with those demands.

However, in recent days the decision by the Maduro-allied Supreme Court against Machado, plus new arrests of opposition members, has prompted a U.S. threat to restore sanctions.

"Unless Maduro and his representatives in Venezuela are able to get back on track, specifically with regard to allowing all presidential candidates to compete in this year's election, we will not be in a position to renew General License 44, which provides relief to Venezuela's oil and gas sector when it comes up for renewal in April," the White House official said.

The official said the U.S. was also considering additional unspecified measures to punish the Venezuelan government.

'AGGRESSIVE ACTION'

"We are very attentive to the actions which could be taken over the coming days which could be considered aggressive," said Jorge Rodriguez, a lawmaker who heads Maduro's team in negotiations with the opposition. "If there is any aggressive action, our response will be serene, reciprocal and energetic."

White House national security spokesman John Kirby said the U.S. measures would depend on Maduro and his government. "They've got till the spring to honor their commitments," he told a daily briefing. "They've got decisions they have to make before we weigh what decisions we'll take."

In the most significant lifting of tough Trump-era sanctions, Washington in October issued a six-month general license authorizing U.S. transactions with Venezuela's vital oil and gas sector and a second license authorizing operations of state gold mining company Minerven. It also removed a U.S. prohibition on secondary-market trading of Venezuelan sovereign bonds.

In recent months, Maduro has allowed the U.S. to send migrants in the country illegally on flights back to Venezuela at a time when U.S. President Joe Biden is struggling with a crisis at the U.S.-Mexico border. U.S. officials have said sanctions relief could curb Venezuelan emigration if the country's dire economic conditions improve.

Machado, a 56-year-old industrial engineer who overwhelmingly won an October opposition primary vote, said on Monday she would not move aside in favor of a substitute.

"There is no retreat. We have a mandate and we will complete it," Machado told a press conference in Caracas.

The ruling was "judicial crime," she said, adding there will be many obstacles still to overcome but there will be elections this year.