Secretary of State Marco Rubio told European counterparts Thursday the US will participate in post-war security guarantees for Ukraine but that the Trump administration believes Europe should take the lead,

The Trump administration has ruled out deploying US troops on the ground in Ukraine, but officials suggest Washington could provide air support.

Trump's transactional diplomacy could involve Europe paying up to $90 billion to ensure U.S. assistance to avoid another Russian invasion of Ukraine.

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.

US and European officials will immediately work on providing Ukraine with robust security guarantees to open a path for a landmark meeting between presidents Vladimir Putin and Volodymyr Zelenskiy, according to people familiar with the matter.

Special U.S. envoy Steve Witkoff says Russian leader Vladimir Putin agreed to allow the U.S. and Europe to offer Ukraine a security guarantee resembling NATO's collective defense mandate.

European NATO leaders must not be naive when discussing a Ukraine peace force but face up to the reality that they would need to deploy tens of thousands of troops to the country for the long term, the head of Germany's soldiers' union said.

For Ukraine, history is a battlefield. Parallels are imprecise, but the current moment resonates with three key chapters in 20th century diplomatic history.