The threats, pressure and ultimatums have come and gone, but Russian President Vladimir Putin has maintained Moscow’s uncompromising demands in Ukraine, raising fears he could use a planned summit with U.

For President Vladimir V. Putin of Russia, it is an opportunity not just to end the Ukraine war on his terms but to split apart the Western security alliance.

A day after US President Donald Trump told European leaders he intended to meet soon with his Russian counterpart Vladimir Putin, gaps have emerged in how Washington and Moscow are characterizing a potential summit.