New U.S. Secretary of Defense Pete Hegseth says it is "unrealistic" to believe that Ukraine will return to its pre-2014 borders.
Hegseth made the statement at a defense summit in Brussels.
Hegseth said that a "realistic assessment of the battlefield" needs to be considered ahead of talks to end the war with Russia.
Trying to return Ukraine to pre-invasion borders will "only prolong the war and cause more suffering," Hegseth said, according to the BBC.
Russia on Wednesday rejected swapping occupied territory with Kyiv as part of any future peace deal
Hegseth is having his first meetings at NATO headquarters with questions looming about European support for Ukraine and their own military spending.
Hegseth downplayed the possibility of Ukraine joining NATO.
Hegseth's two days of talk in Brussels with his counterparts from NATO and Ukraine are part of a flurry of visits to Europe this week by top US officials.
Those will culminate with Vice President JD Vance meeting Ukrainian President Volodymyr Zelensky at a security conference in Munich on Friday.
Trump's return to the White House has set nerves on edge as he pushes his "America First" agenda and has questioned US security commitments in Europe.
