The deal was limited, and it was not clear when or how it would start. The Kremlin also demanded some Western sanctions be lifted first.

When the U.S. said it had reached an agreement to eliminate the use of force in the Black Sea, it looked like a breakthrough. Then Russia listed its conditions.

The White House said Tuesday that both Ukraine and Russia have agreed to stop using force in the Black Sea – a deal in principle that the Kremlin says comes with several conditions before it can be implemented.