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.

The U.S. official, who was speaking on condition of anonymity, said the U.S. General Dan Caine, the chairman of the Joint Chiefs of Staff, was expected to attend the meeting virtually, but plans could still change.