U.S. Vice President Joe Biden and Ukrainian President Petro Poroshenko have agreed that the future of sanctions against Russia must be linked to the full implementation of a peace agreement reached last month in Minsk.
The White House said Biden spoke with Poroshenko by phone on March 18.
"As long as Russia continues to fuel violence and instability in Ukraine, the international community must be prepared to increase the costs to Russia for pursuing such actions," it said in a statement.
Biden also welcomed the Ukrainian parliament vote on March 17 to confer special status on rebel-controlled eastern regions and grant them limited self-rule, but only after local elections are held under Ukrainian law.
Russia and the rebels reject that condition. Russian Foreign Minister Sergei Lavrov said on March 18 that the Ukrainian parliament had sought to "rewrite" the agreement reached on February 12 in the Belarusian capital.
In Kyiv, Prime Minister Arseniy Yatsenyuk said that no one on the Ukrainian side had much optimism that Russia "and the terrorists" would readily fulfill the Minsk plan.