WASHINGTON (Reuters) – The U.S. Treasury Department on Tuesday issued a new license to Chevron Corp, the last major U.S. oil company still operating in Venezuela, giving it until June 3 to wind down its joint ventures in the OPEC member nation.

The United States last year imposed sanctions barring imports of Venezuelan oil and transactions made in U.S. dollars with Venezuela’s state-run oil company PDVSA, a move designed to starve the country of oil dollars and oust socialist President Nicolas Maduro.

Chevron has had a special U.S. operating license exempting it from sanctions on Venezuela’s vital oil sector since January, but the latest waiver was due to expire on Dec. 1.

The new license, which also applies to Halliburton, Schlumberger Ltd , GE company Baker Hughes and Weatherford International, continues the restrictions imposed in the last waiver and does not authorize the companies to drill, sell, ship or trade Venezuelan oil.

The companies are also not authorized to repair or improve wells, hire additional staff or services, pay dividends to Venezuelan state-run PDVSA or negotiate any new loans.

The license allows the companies only to conduct transactions with PDVSA “necessary for the limited maintenance of essential operations in Venezuela or the wind down of operations” by June 3.

The Trump administration has waged a “maximum pressure” campaign of sanctions and diplomatic measures in an effort to oust Maduro, whose 2018 re-election was considered a sham by most Western countries.

But Maduro remains in power, backed by Venezuela’s military as well as Russia, China and Cuba. Some U.S. officials have said this has been a growing source of frustration for President Donald Trump.