The United States on Thursday extended by one month to ​June 27 a license allowing companies ‌to hold talks with Russia's second-largest oil producer Lukoil (LKOH.MM), opens new tab on buying its foreign assets, ​the U.S. Treasury Department said.

The U.S. ​has now extended the deadline about six ⁠times since imposing sanctions last October ​on Lukoil and state-owned Rosneft (ROSN.MM), opens new tab  for ​the role their revenues play in supporting the more than four-year war in Ukraine.

Any deal must ensure that Lukoil ​receives no upfront payment, with ​all ⁠proceeds placed in a frozen account under U.S. jurisdiction. Transactions also require final approval ⁠from ​the Treasury Department's Office ​of Foreign Assets Control.