Russia blocked an effort to enhance transparency around major military exercises in Europe, drawing a rebuke from a U.S. diplomat at a security forum in Milan, Italy.

“A large majority of the states around this table supported that effort, but Russia made it clear it did not see a need for military transparency,” Assistant Secretary of State Wess Mitchell told the Organization for Security and Cooperation for Europe.

The United States had hoped to update an agreement governing military exercises in Europe, an effort that might have eased Ukrainian fears of Russia using such drills to set the stage for expanding the invasion of the former Soviet satellite state. Mitchell’s remonstrance over the military exercises punctuated a litany of Russian misbehavior on the continent, especially with respect to the ongoing crisis in Ukraine.

“Today, we had hoped to welcome agreement on some initial steps to update the OSCE Vienna Document to help mitigate concerns regarding large-scale military exercises occurring ever more frequently on the continent,” said Mitchell. “We should intensify our efforts next year with the goal of issuing an updated Vienna Document at the end of 2019.”

Russia has conducted large-scale drills on both its western and eastern borders over the last 15 months, drawing alarm from Ukrainian President Petro Poroshenko.

“Seven thousand flatcars with troops and hardware have approached the territory of Ukraine, and unfortunately there are no guarantees that after the drill is over they will all return home,” Poroshenko said last year, per the BBC.

Russian Foreign Minister Sergey Lavrov countered that the U.S. and other Western powers took the first aggressive step, alleging that they “back[ed] a coup d’etat in Ukraine” that overthrew pro-Russian Viktor Yanukovych, who was removed from office by the Ukrainian Parliament and left the country in the company of Russian forces.

"NATO’s reckless expansion, the buildup of the alliance’s potential both on the so-called eastern flank and the deployment of the U.S. missile defense system to Europe, and illegitimate sanctions under forged pretexts — all this has resulted in a crisis of trust in the Euro-Atlantic,” Lavrov said at the OSCE conference.

But Mitchell, speaking two days after the U.S. declared that Russia committed a “material breach” of a major Cold War era nuclear arms control treaty, maintained that Moscow is responsible for the Ukraine crisis and the broader tensions with the West.

“Russia’s destabilizing actions have prompted NATO Allies to enhance their deterrence and defense posture,” Mitchell told the OSCE Ministerial Council. “In the past four years, Russia has precipitated Europe’s largest humanitarian crisis in a generation — one that has cost more than 10,000 casualties in eastern Ukraine, and displaced more than 1.5 million people from their homes. ... The OSCE should not mince words when assigning responsibility for these acts.”