Ukrainian President Petro Poroshenko has warned that Ukrainians may become disillusioned with their pro-European path if the European Union further delays closer integration with Kyiv.
The EU agreed to provide visa waivers for Ukrainians last month after weeks of stalling, but the decision has not gone into effect.
"To delay further would be flagrantly unfair as Ukraine has paid a high price," Poroshenko told foreign ambassadors to Ukraine on January 16.
"It would also be dangerous because more unreasonable delays would undermine Ukrainians' faith in Europe. This is exactly what Russia wants," he said, adding that Ukraine's EU Association Agreement also should be ratified.
Delays have raised criticism that the bloc was reneging on pledges to help Ukraine as it seeks to move away from Moscow's orbit in the wake of a 2013 uprising that ousted a Kremlin-backed president.
After the change in power, Russia annexed Ukraine's Crimea region and is accused by Kyiv and NATO of fueling a pro-Russia separatist conflict in eastern Ukraine.
"We are all witnesses to efforts to build a new iron curtain and it is today's Russia that is building it," Poroshenko said.