Top US Air Force officials said on Wednesday that US-made fighter jets are one option for Ukraine as it rebuilds its air force to face Russia, appearing to soften the US’s reluctance to provide such advanced weaponry.

Ukraine has lobbied the United States to supply fighter jets, particularly F-15s and F-16s, to counter Russia’s larger and technologically superior force. The US has declined, despite the fact that it and other countries have supplied Ukraine with spare aircraft parts and other weapons throughout the conflict.

Ukraine’s air force, which uses many of the same Soviet-era planes as Russia, has fought well but suffered heavy losses. On Wednesday, US Air Force Chief of Staff Gen. Charles Q. Brown told the Aspen Security Conference in Colorado that Ukraine was unlikely to receive more Russian hardware but had several options for rebuilding its fighter fleet.

Brown stated that, in addition to US-made aircraft, “There’s the Swedish Gripen. The Eurofighter is one option. There’s also the Rafale. So there are a variety of platforms that could go to Ukraine. MiGs, most likely.”

Later in the same conference, Air Force Secretary Frank Kendall stated that “older” US aircraft “are a possibility” for Ukraine.

Kendall was specifically asked about providing A-10 ground-attack aircraft that the US Air Force is looking to retire, but he declined to elaborate on which planes might be given to Ukraine. ” “We will be open to discussions with them about their needs and how we might be able to meet them,” Kendall said.

Brown spoke hours after telling Reuters that the United States and its allies were looking into training Ukrainian pilots as part of a possible “long-term plan” to help Ukraine’s air force. Brown said that whether and when Ukrainian pilots could train on new jets would be determined by the state of the war and their ability to leave Ukraine for the training.

Brown told Reuters that the transition away from Soviet-designed aircraft would be difficult, but that input from NATO allies and partners who have abandoned Soviet-made hardware could “be helpful” as Ukraine makes the switch.

Brown’s remarks come just days after the House passed its version of the National Defense Authorization Act, authorizing $840 billion in US defense spending in 2023. The bill included a provision authorizing $100 million in aid to Ukraine for “training and familiarity building” on US aircraft, as well as “fostering a better understanding of the air platforms, tactics, and techniques” used by the US and other NATO militaries.

While neither Brown nor Kendall provided specifics on what jets or training could be provided to Ukraine, the remarks appear to be a departure from previous reservations about supplying Ukraine with more advanced aircraft.

Brown did say on Wednesday that any future training efforts would be based on the US’s longstanding relationship with Ukraine.

Brown stated that officials “had a lot of time to talk about how we train together for our common defense, and it’s no different with Ukraine” at the Global Air and Space Chiefs’ Conference earlier this month in London.

“Part of this is understanding where Ukraine wants to go and how we meet them where they are, and then looking at capabilities not only from the US but from all of our allies and partners who have an interest in ensuring that Ukraine can provide for its own security,” Brown added.

Russian air force operations in Ukraine have surprised observers and led analysts to believe that Russian military aviation is not as capable as previously assumed.

Brown, who assumed his current position in August 2020, warned early in his tenure that a major conflict would most likely be costly to the US Air Force. Brown stated on Wednesday that, despite Russia’s poor air performance, the war in Ukraine provides more evidence that future wars will be more difficult than those in the recent past.

“We’ve spent the last 30 years operating in areas where air superiority was not necessarily contested. That will not be the case in the future “Brown stated.