BERLIN/KYIV/WASHINGTON, Dec 15 (Reuters) - The United States has offered to provide NATO-style security guarantees for Kyiv as U.S. and European negotiators reported progress in talks on Monday to end Russia's war in Ukraine, but a deal on territorial concessions remained elusive.
Envoys sent by U.S. President Donald Trump made the unprecedented offer at talks with Ukrainian President Volodymyr Zelenskiy in Berlin, U.S. officials said, but warned such a deal would not be on the table forever.
