U.S. and European military planners have begun exploring post-conflict security guarantees for Ukraine, U.S. officials and sources told Reuters on Tuesday, following President Donald Trump's pledge to help protect the country under any deal to end Russia's war.

NATO military leaders are expected to meet on Wednesday to discuss Ukraine and the way forward, U.S. and NATO officials said on Tuesday, as Washington and European capitals work out details of what security guarantees might look like for Kyiv.