Russian Foreign Minister Sergei Lavrov has accused "someone in the European Union" of trying to ensure that a cease-fire in eastern Ukraine fails.
Officials from Russia, Ukraine, and the OSCE are expected to convene for an emergency meeting in Minsk on May 6 to discuss the implementation of the cease-fire agreed in the Belarusian capital, Minsk, on February 12.
Lavrov, at a news conference in Moscow, accused the EU of turning a blind eye to attacks which have killed civilians in rebel-held areas.
"Judging by certain signs, someone in the European Union wants the EU to allow the Ukrainian government not to implement the Minsk agreements," he said after talks with Austrian Foreign Minister Sebastian Kurz.
He also described what he called increased military activity by Ukrainian forces in recent weeks as an attempt to tear up the cease-fire accord.
The EU did not immediately respond to Lavrov's remarks.
In Kyiv, Ukrainian military spokesman Andriy Lysenko said the separatists were building up military equipment for more attacks.