Military chiefs from the United States and a number of European countries on Thursday presented options to their national security advisers for providing security guarantees to Ukraine, officials said, Reuters reported.

This followed US President Donald Trump's pledge to help protect the country under any deal to end Russia's 3-1/2-year-old war in Ukraine.

A Pentagon statement said U.S. and European planners had developed the military options for "appropriate consideration" by allied national security advisers. Reuters was first to report that the military leaders were preparing the options, according to Reuters.