KIEV — A US-backed deal to settle the crisis in eastern Ukraine fell flat Friday as pro-Russian militants vowed to stay in occupied government buildings, dashing hopes of a swift end to an insurgency that the authorities in Kiev portray as a Kremlin-orchestrated effort to put Ukraine’s industrial heartland under Russian control.
But the agreement, reached in Geneva on Thursday by diplomats from the European Union, Russia, Ukraine and the United States, appeared to arrest, at least temporarily, the momentum of separatist unrest in Ukraine’s Russian-speaking east. Armed pro-Russian militants, who have seized buildings in at least 10 towns and cities since Feb. 6, paused their efforts to purge all central government authority from the populous Donetsk region.
It was clear that for the pact to have a chance of success, the Kremlin would have to pressure the militants to leave the buildings they had seized.
It has shown no inclination to do so, blaming the Ukrainian government for the turmoil and denying that Russia has any ties to the rebels.
With militants vowing to ignore the agreement but halting what had been a daily expansion of territory under their control, officials in Kiev, the capital, voiced some hope that a settlement was still possible.
They were skeptical, however, about Russia’s willingness to push the separatists to disarm and vacate occupied buildings.
“If Russia is responsible before not just Ukraine but the world community, it should prove it,” said Andrii Deshchytsia, the acting Ukrainian foreign minister, who took part in the Geneva talks.
Western officials said the United States planned to reassure Eastern European NATO members conducting company-size ground-force exercises in Estonia and Poland. A company is about 150 troops.
The exercises would last a couple of weeks and would most likely be followed by other troop rotations in the region.
Doubts about the Kremlin’s readiness to push pro-Russian militants to surrender their guns have been strengthened by its insistence that it has no hand in or control over the separatist unrest, which Washington and Kiev believe is the result of a covert Russian operation involving, in some places, the direct action of special forces.
“I don’t know Russia’s intentions,” Deshchytsia said, noting that during the negotiations, Russia’s foreign minister, Sergei V. Lavrov, had repeatedly asserted “that Russia was not involved.” He said Lavrov had been “cooperative and aggressive at the same time.”
Russia’s denials have stirred concerns that it went along with the agreement not to curb the turmoil in eastern Ukraine, but to blunt US and European calls for tougher sanctions that could severely damage Russia’s already sickly economy. Western sanctions have been limited to a travel ban and asset freeze on a few dozen individuals and a Russian bank.
Secretary of State John Kerry called Lavrov on Friday and urged Russia to ensure “full and immediate compliance” with the agreement, a senior State Department official said. Kerry, the official added, “made clear that the next few days would be a pivotal period for all sides to implement the statement’s provisions, particularly that all illegal armed groups must be disarmed and all illegally seized buildings must be returned to legitimate owners.”
Kerry also spoke with Ukraine’s prime minister and praised him for moving to carry out the deal, including by increasing transparency and guaranteeing amnesty for militants who disarm and leave occupied buildings.
In Washington on Friday, Susan E. Rice, President Obama’s national security adviser, denounced anti-Semitic fliers distributed in Donetsk, which instructed Jewish residents to “register,” as “utterly sickening” and said Obama had “expressed his disgust quite bluntly.”
“They have no place in the 21st century,” she said.
US officials gave no firm timeline for when they expect militants to pull back but said it should be days, not weeks. Vice President Joe Biden is scheduled to travel to Ukraine on Tuesday, which could be a moment to assess whether the agreement has yielded results.
Russia responded with fury Friday to remarks the day before by Obama, who said the deal offered a “glimmer of hope” but that the United States would take more punitive action if Russia did not abide by it.