Washington (CNN) -- Tensions between the United States and Russia over the crisis in Crimea have exploded into an open row as Russia rejects U.S. diplomatic efforts to solve the impasse.
Russian Foreign Minister Sergey Lavrov said Monday that U.S. Secretary of State John Kerry postponed a face-to-face meeting with Russian President Vladimir Putin to discuss American proposals, which Moscow has effectively rejected, on solving the crisis.
The meeting, which Russia said was supposed to happen Monday, would have marked the highest-level contact between the two countries since Russian troops took up positions in Crimea, and would have come ahead of Sunday's potentially explosive vote on whether Crimea should split from Ukraine and join Russia.