March 30 (Reuters) - The U.S. on Monday extended a deadline for the fourth time for companies to negotiate with Russia's Lukoil about buying its foreign assets after Washington imposed sanctions on the energy company last year.

The U.S. Office of Foreign Assets Control extended the deadline this time by a month to May 1 for companies interested in buying the foreign assets that are worth about $22 billion.

Washington imposed sanctions in October on Lukoil, Russia's second-largest oil producer, and Rosneft, its top producer, to reduce Moscow's ability to pay for its war on Ukraine.

Parties interested in the assets have included U.S. private equity firm Carlyle, U.S. oil majors Exxon Mobil and Chevron Corp, Abu Dhabi conglomerate International Holding Company, and Austrian investor Bernd Bergmair, the former majority owner of an adult entertainment group that includes website Pornhub.

Any specific deals struck with Lukoil over the assets will require OFAC approval.

The Trump administration slowed the sale of Lukoil's international assets to pressure Russia in Ukraine peace talks, four sources told Reuters in February.

(Reporting by Timothy Gardner and Costas Pitas; editing by Daphne Psaledakis and Rod Nickel)