The decision left officials on both sides of the Atlantic scrambling to find out how long the pause might last.

The move "was made to put America’s interests first," a White House spokeswoman said, as U.S. munitions have been depleted in recent years.

The call between Trump and Putin comes just one day after Washington indirectly aided Putin’s war effort against Ukraine by suspending some shipments of air defense missiles, artillery shells and other weapons as part of what Pentagon officials have described as a pause of arms shipments globally while the U.S. replenishes its own stockpiles.