MOSCOW — Russia on Saturday accused Ukraine’s opposition of failing to fulfill its side of a peace deal intended to end the nation’s political crisis and urged the West to intervene.

Russia’s Foreign Ministry said President Vladimir Putin in Friday’s phone conversation with President Barack Obama urged him to “use every opportunity to stop illegal actions by the radicals and return the situation to the constitutional field.”

On Saturday, Foreign Minister Sergey Lavrov spoke to U.S. Secretary of State John Kerry, telling him that opposition supporters refused to surrender their weapons and effectively have taken the Ukrainian capital under their control, the ministry said.

Earlier in the day, Lavrov also called his German, French and Polish counterparts, who helped broker Friday’s agreement between Ukrainian President Viktor Yanukovych and the opposition. Yanukovych agreed to hold early elections this fall and surrender much of his powers, but opposition supporters have kept pushing for his immediate dismissal.

The Russian Foreign Ministry said Lavrov urged his counterparts to use their influence with the Ukrainian opposition, which he said “not only has failed to fulfill any of its obligations, but keeps making new demands under the influence of armed extremists and rioters.”

Their actions “pose a direct threat to Ukraine’s sovereignty and constitutional order,” he said.