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.

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

Two Chevron-chartered vessels are stalled, and loading permits for four others are suspended, impacting the US company's exports. Venezuela blames US measures, stating Chevron couldn't pay for the oil,