The government of Poland announced on Tuesday that it intended to transfer twenty-eight Soviet-era MiG-29 fighter jets to the United States, theoretically allowing Washington to forward them to Ukraine to be used in the war against Russia.

The Polish Foreign Ministry, which said that the transfer would be “immediate … and free of charge,” indicated that the jets would be transferred to the U.S. Air Force’s base in Ramstein, Germany. In return for its donation, Poland requested that the United States compensate it with American fighter jets with “corresponding capabilities”—essentially a request for U.S.-made F-16s, a fighter from the same era which has assumed many of the same roles as the MiG-29 for American and allied air forces.

The Polish statement came after more than a week of negotiations between the United States and Poland, which has used MiG fighters in its air force since before the fall of the Soviet Union. Ukrainian president Volodymyr Zelensky has requested that NATO resupply Ukraine with MiG fighters, which Ukrainian pilots know how to operate. However, Russia has indicated that it would view the flying of NATO planes into Ukraine as an act of war, potentially inviting a nuclear confrontation between Moscow and the West.

For this reason, Poland’s announcement led to controversy in the United States, as many commentators viewed it as a Polish attempt to make the United States responsible for finding a way to safely transport the MiGs to Ukraine. Policymakers in Washington also indicated that Polish officials had not informed their American counterparts of the plan before making it public, with Undersecretary of State for Foreign Affairs Victoria Nuland describing it as a “surprise move.”

The Defense Department later indicated that it had refused Poland’s proposal, with Pentagon spokesman John Kirby warning that “fighter jets ‘at the disposal of the Government of the United States of America’ departing from a U.S./NATO base in Germany to fly into airspace that is contested with Russia … raises serious concerns for the entire NATO alliance.”

“We will continue to consult with Poland and our other NATO allies about this issue and the difficult logistical challenges it presents, but we do not believe Poland’s proposal is a tenable one,” Kirby said.

The airspace over Ukraine is still contested between Moscow and Kiev. While the Ukrainian military has scored massive victories—as many as nine Russian aircraft were shot down by Ukrainian defenders on March 6—Russia’s air force remains far larger than Ukraine’s, and much of it has not been committed to the conflict yet.

Trevor Filseth is a current and foreign affairs writer for the National Interest.

Image: Reuters.