Venezuela's state oil company PDVSA has canceled several authorizations it had granted U.S.-based producer Chevron to load and export Venezuelan crude in April, three sources with knowledge of the decision said on Thursday.

Chevron Corp. was ordered to return nearly 1 million barrels of Venezuelan oil to Petroleos de Venezuela SA in a blow to the oil major, which was working to secure crude before wrapping up operations in the country when a US sanctions deadline hits in May.

This development comes after Washington cancelled key licences last month for several PDVSA partners including Chevron.