SINGAPORE/MEXICO CITY (Reuters) - China National Petroleum Corp, a leading buyer of Venezuelan oil, has halted August loadings following the latest U.S. sanctions on the South American exporter, three sources with direct knowledge of the matter told Reuters on Monday.

FILE PHOTO - Workers are seen near pumpjacks at a China National Petroleum Corp (CNPC) oil field in Bayingol, Xinjiang Uighur Autonomous Region, China August 7, 2019. REUTERS/Stringer

The Trump administration in early August froze all Venezuelan government assets in the United States and U.S. officials ratcheted up threats against companies that do business with Venezuela’s state-run oil company, Petróleos de Venezuela, S.A., or PDVSA.

“Trump’s executive order gave a directive for the follow-up sanction measures that shall be announced by the U.S. Treasury... CNPC is worried that the company is likely to be hit by the secondary sanctions,” said one source.

A CNPC spokesman declined to comment. PDVSA and Venezuela’s information ministry did not immediately respond to requests for comment.

A second person, an executive with a large marketer of Venezuelan oil in China, said his company had been notified of the suspension.

“We were told that Chinaoil will not load any oil in August. We don’t know what will happen after,” he said.

Chinaoil is the trading vehicle of CNPC that buys most Venezuelan crude under term contracts and is one of Caracas’ top clients. PetroChina, another of CNPC’s subsidiaries, also is a direct buyer of Venezuelan oil. Both were struggling to charter vessels willing to load at the OPEC-member nation’s ports due to sanctions, according to traders.

The suspension caught PDVSA by surprise, according to one of the sources, but it could be temporary if CNPC is able to put in place a new arrangement excluding units involved in businesses with the United States. A new deal has not yet been reached, two separate sources with knowledge of the decision said.

The sources declined to be identified as they are not authorized to speak to the media.

Most deliveries of Venezuelan oil and refined products to CNPC’s units are intended to monetize billions of dollars lent by China to Venezuela through oil-for-loan pacts. PDVSA has never failed to deliver crude to China to pay off debts, although refinancing and grace periods have been agreed upon over the last decade to ease the debt burden.

CNPC will wait for more guidelines from the U.S. Treasury before further moves in dealing with Venezuelan oil, one of the sources said.

The suspension followed recent communications between the U.S. and Chinese governments, including a meeting between U.S. embassy officials in Beijing and top management at CNPC, the source added.

The White House imposed sanctions on Venezuela’s oil industry in January in an effort to unseat socialist President Nicolas Maduro, whose re-election in 2018 is viewed by much of the Western Hemisphere as illegitimate.

The executive order Trump issued on Aug. 5 did not explicitly sanction non-U.S. companies that do business with Venezuela’s state-run PDVSA, including partners in crude operations like France’s Total SA, Norway’s Equinor ASA, as well as Russian and Chinese customers.

However, the order threatens to freeze U.S. assets of any person or company determined to have “materially assisted” the Venezuelan government.

Beijing has become increasingly pragmatic in recent years in an amply supplied global oil market and as Venezuela’s economy plunged deeper into recession.

For the first six months of this year, China imported 8.67 million tonnes of crude oil from Venezuela, or roughly 350,000 barrels per day, about 3.5% of its total imports, according to Chinese customs data.

In July, Venezuela exported 563,000 bpd of crude and fuel to China, mostly through CNPC and Russia’s Rosneft, according to the PDVSA’s internal data and Refinitiv Eikon vessel tracking data. The nation is now Venezuela’s primary destination for its oil.