KIEV/SLAVIANSK, Ukraine — An international agreement to avert wider conflict in Ukraine was faltering on Monday, with pro-Moscow separatist gunmen showing no sign of surrendering government buildings they have seized.
U.S. and European officials say they will hold Moscow responsible and impose new economic sanctions if the separatists do not clear out of government buildings they have occupied across swathes of eastern Ukraine over the past two weeks.
Washington, which signed last week's accord along with Moscow, Kiev and the European Union, held open the possibility of slapping sanctions on Russian President Vladimir Putin personally, but suggested no such step would be taken soon.
U.S. Secretary of State John Kerry urged his Russian counterpart Sergei Lavrov on Monday to help secure the Geneva deal, including by "publicly calling on separatists to vacate illegal buildings and checkpoints", spokeswoman Jen Psaki said.
The United States and EU have imposed visa bans and asset freezes on some Russians over Moscow's annexation of Crimea from Ukraine last month. These limited measures, designed not to have wider economic impact and to avoid deepening the crisis, have been mocked as pointless by Moscow.
Psaki said tougher measures may be in store. But she noted that the U.S. goal was easing the crisis rather than imposing more sanctions.
Washington and Brussels both say they are working on tougher measures they will impose unless Russia's allies in eastern Ukraine back down, although building a consensus is tricky in Europe where many countries rely on Russian energy exports.
In its account of their telephone conversation, the Russian Foreign Ministry said Lavrov had called on Kerry to "influence Kiev, not let hotheads there provoke a bloody conflict" and to encourage it "to fulfill its obligations unflaggingly".
U.S. Vice President Joe Biden arrived in Kiev Monday, where he is expected to announce a package of technical assistance. The visit is likely to be more important as a symbol of support than for any specific promises Biden makes in public.
The Geneva accord aimed to lower tension in the worst confrontation between Russia and the West since the Cold War. Its calls for occupied buildings to be vacated under the auspices of the Organization for Security and Cooperation in Europe (OSCE).
But no sooner had the accord been signed than both sides accused the other of breaking it, while the pro-Moscow rebels disavowed the pledge to withdraw from occupied buildings.