US oil producer Chevron Corp and several European companies are in talks with the Trump administration to obtain authorizations to keep their stakes in joint ventures with Venezuela’s state-run PDVSA, three sources close to the matter said.

Washington in March revoked licenses and authorizations it had granted in recent years that allowed PDVSA’s foreign partners and customers to do business with Venezuela, which is under US sanctions, and export oil to destinations including the US, Europe and India.

The US gave the companies until May 27 to wind down transactions, but did not rule specifically on what they should do with employees and assets in Venezuela, including joint venture stakes.

Lawyers and experts have said more clarity is needed to complete the closure of those activities. PDVSA has in the meantime only been delivering oil to customers who prepay or agree to swaps, and in April canceled a handful of crude cargoes to Chevron amid payment uncertainty.