U.S. military refueling aircraft have begun departing Vasil Levski Airport in Sofia after completing their mission in Bulgaria.

Axar.az reports, citing the Bulgarian News Agency (BTA), Bulgarian Prime Minister Rumen Radev said at the start of the regular Cabinet meeting that, as promised, the aircraft left Sofia within the agreed timeframe, minimizing the risk of potential attacks near the Bulgarian capital.

"So far, four U.S. aircraft have departed from Vasil Levski Airport in Sofia, and all of them will leave gradually by Monday," Bulgaria's Ministry of Defense said on Saturday.

On May 29, the Bulgarian government approved an extension until June 30 for the stay of up to 15 U.S. aircraft, along with their personnel and equipment.

At the end of February, then-interim Defense Minister Atanas Zapryanov told parliament that 10 KC-135 Boeing Stratotanker aerial refueling aircraft had been deployed at Vasil Levski Airport on February 25. He noted that while the number of aircraft changes daily, it cannot exceed the authorized limit of 15.

Earlier, the United States did not give a positive response to Bulgaria's request to join the Visa Waiver Program. Sofia subsequently announced that the deployment of U.S. tanker aircraft would be extended by only one month.