At least two vessels carrying Venezuelan crude chartered by Chevron are stalled due to state oil company PDVSA canceling their export authorizations, according to shipping data and sources, as the government had no certainty of payment amid the hardening of U.

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.

Chevrons Venezuelan crude shipments have hit a roadblock as PDVSA, Venezuelas state oil company, revoked export authorizations for several tankers due to payment uncertainties linked to renewed U.S. sanctions.