Shortly after the four-way talks between France, Germany, Russia and Ukraine concluded in Minsk, the White House welcomed the new deal as a "potentially significant step" but expressed concern over reports of fresh clashes in eastern Ukraine.
While urging all parties to maintain "complete restraint" in the run-up to the Sunday ceasefire, U.S. Secretary of State John Kerry called for an immediate halt to the Russian and separatist assault on Debaltseve and other Ukrainian towns in a statement, the BBC reported.
Kerry added that the sanctions on Russia could be lifted only if the new peace deal was respected.
Earlier, German Chancellor Angela Merkel too had warned Moscow that it will face a new wave of sanctions if a deal to end the Ukraine conflict is not implemented fully.
The ceasefire is due to take effect in eastern Ukraine at midnight on Saturday but both sides remain skeptical.
Pro-Russia separatists too have signed the deal, which includes weapon withdrawals and prisoner exchanges. However, key issues still remain to be settled.
