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.

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

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.