China’s largest energy company, the China National Petroleum Corporation (CNPC), is backing away from direct purchases of Venezuelan crude as the United States tightens sanctions against Caracas.

CNPC has cancelled plans to load about five million barrels of Venezuelan oil onto ships this month, Qatar News Agency reported. This comes after the latest executive order from US President Donald Trump, ratcheting up threats against companies that do business with Venezuela.

It is thought to be the first time in 10 years that Beijing has refused to buy Venezuelan oil, and follows a meeting between CNPC executives and senior US diplomats, a source told Reuters news agency.

Chinese and international media said an interruption in August would not mean a complete break in communication between China and Venezuela over oil.

Washington froze Venezuelan government assets held in the US in early August. Further guidelines are expected to be issued by the US Treasury, but the Trump administration has been trying to unseat socialist President Nicolas Maduro since at least his 2018 re-election.

Trump’s executive order on August 5 did not explicitly prohibit non-US companies from doing business with Venezuela’s state-run company PDVSA but did threaten to freeze US assets of any person or company determined to have “materially assisted” the Venezuelan government.