HOUSTON (Reuters) -The U.S. government has notified foreign partners of Venezuela's state oil company PDVSA of the imminent cancellation of authorizations that allow them to export Venezuelan oil and byproducts, sources close to the decision by President Donald Trump's administration said on Saturday.

In recent years, former President Joe Biden's administration granted the authorizations to secure Venezuelan oil for refineries from Spain to India as exceptions to the U.S. sanction regime on the South American country.

The companies that had received licenses and comfort letters from Washington include Spain's Repsol, Italy's Eni, France's Maurel & Prom, India's Reliance Industries and U.S. Global Oil Terminals.

Most companies had already suspended imports of Venezuelan oil following Trump's imposition this week of secondary tariffs on buyers of Venezuelan oil and gas, according to sources and vessel tracking data.

The combination of tariffs and license cancellations to enforce sanctions is expected to squeeze Venezuela's oil exports in the coming months, after they began to decline in March, according to the data.

In February, Venezuela exported 910,000 barrels per day of crude and fuel, above January's 867,000 bpd.

Similar measures by Trump's first administration in 2020 knocked down Venezuela's oil output and exports, creating the need for PDVSA to use intermediaries to allocate cargoes to China, and leading to a pact with Iran. Those middlemen still do business with PDVSA.

PDVSA, Repsol, Eni, Maurel & Prom, Reliance and the U.S. State Department did not immediately reply to requests for comment. Global Oil could not be reached for comment. The U.S. Treasury Department declined to comment.

Last month, Trump said a key license to U.S. producer Chevron ( CVX ) to operate in Venezuela and export crude to the U.S. would be canceled. Days later, the Treasury Department ordered the company to wind down Venezuelan operations, and last week extended the deadline to May 27.

The withdrawal of the most important U.S. license for Venezuela's energy industry has sent a strong signal of Washington's policy change toward Venezuela as Trump's administration also curbs migration, with a special focus on Venezuelans illegally in the U.S.

Following reports by international observers of irregularities in President Nicolas Maduro's 2024 reelection, Trump has ramped up pressure on his government while accusing him of failing to make progress on electoral reforms and migrant returns.

It was not immediately clear if all PDVSA partners were given the same May 27 deadline to wind down operations. The terms of Chevron's ( CVX ) license termination also have not been completely clarified.

U.S. Secretary of State Marco Rubio said this month that foreign oil companies in Venezuela would receive new guidance.

Maduro has criticized the sanctions, saying they amount to an "economic war."

(Reporting by Marianna Parraga, additional reporting by and Stefanie Escenbacher; Editing by David Gregorio and Rod Nickel)