The United Nations is urging all sides in the Ukraine conflict to fully respect the cease-fire agreement reached earlier this year.
It issued the call as top U.S. defense officials and diplomats were due to meet Friday at the headquarters of U.S. European Command in Stuttgart, Germany, to review the effectiveness of EU and U.S. economic sanctions against Russia and NATO's strategy in deterring further Russian actions in Ukraine.
"We are either looking at a return to a deepening, intractable conflict or a momentary upsurge in parts of the conflict zone. We cannot afford either scenario," U.N. political chief Jeffrey Feltman told an emergency Security Council meeting Friday.
Speaking via a video link from Kyiv, the deputy chief of the Organization for Security and Cooperation in Europe's Monitoring Mission in Ukraine, Alexander Hug, told the meeting that hostilities this week in the town of Marinka were a new, worrying development. He said violence had also spread to the Luhansk region, with villages north of the city experiencing regular shelling and small-arms fire.
Hug said the OSCE’s 375 monitors had also noted changes in heavy weaponry, with some armaments having been moved to areas forbidden under the Minsk agreement and others that were previously accounted for now missing. He said drones belonging to the monitoring mission had been jammed on a regular basis and the monitors had faced threats and intimidation and had even been shot at.
“Our assessment from the ground is that tension levels have increased and that cease-fire violations are becoming more frequent as well as more severe," he said. "In particular, the recent reintroduction of Grad rockets and other multiple launch rocket systems is cause for added concern.”
Ukraine's ambassador to the U.N., Yuriy Sergeyev, said Russia and Russia-backed separatists in eastern Ukraine were guilty of “grave violations” of the cease-fire agreement.
The Russian and U.S. representatives to the world body had a sharp exchange over responsibility for the latest escalation of fighting in eastern Ukraine.
Russian Ambassador Vitaly Churkin accused Ukrainian forces of regularly shelling cities and villages in rebel-controlled areas — thereby, in his words, "terrorizing the local population."
He called on Security Council members who have influence on Ukraine's government to work to prevent a "further escalation of conflict" — which, he said, would have “unpredictable consequences.”
U.S. Ambassador Samantha Power said in response that “the recent violence [in eastern Ukraine] is rooted in a combined Russian-separatist assault."
Power said Kyiv had made a good-faith effort to honor its cease-fire commitments, despite what she called “seemingly endless” violations by Russia and the separatists. She said Russia — "and the separatists it trains, arms, fights alongside, and with whom it shares command-and-control systems in eastern Ukraine" — had continued to flout the commitments made at Minsk. "It goes right on applying its playbook in new territories, as though this council and the world are too blind or too easily deceived to notice."
Churkin disputed the notion that Kyiv has been implementing the Minsk agreement, saying the government was moving slowly on several fronts, including adopting an amnesty law and starting dialogue for local elections in the east.
Power is to travel to Kyiv next week to meet with Ukrainian politicians and assess the situation firsthand.
Fighting in Marinka this week left at least 28 people dead. The government-controlled town is located in the western suburbs of the rebel-controlled city of Donetsk.
More than 6,400 people have been killed since April 2014, when Russia-backed separatists in eastern Ukraine launched a rebellion against Kyiv.
On Thursday, Ukrainian President Petro Poroshenko told parliament that Ukraine's military must prepare to defend the country against a possible "full-scale invasion" by Russia. He said there was a "colossal threat" that large-scale fighting could resume, and that 9,000 Russian troops were already inside eastern Ukraine.
Responding to the escalating violence, the White House on Thursday said President Barack Obama would urge European Union leaders at the upcoming G7 summit in Germany to maintain sanctions against Moscow for its "aggression in eastern Ukraine."
White House spokesman Josh Earnest acknowledged Thursday that economic pressure had not yet led Russian President Vladimir Putin to change his "strategic calculus inside Ukraine."
On Friday, Obama spoke by telephone with Ukrainian President Petro Poroshenko and expressed his deep concern about increased fighting in eastern Ukraine. The White House said the two leaders also called on Russia to abide by the terms of the February cease-fire.
EU member countries will vote later this year on whether to continue their sanctions against Russia. U.S. deputy national security adviser Ben Rhodes said maintaining the sanctions is "the right course ... against more aggressive Russian action." He also said they needed more time to work.
The Kremlin insists it has no direct role in the fighting in eastern Ukraine and has repeatedly denied supporting rebels with arms and fighters.
A truce signed by Russia, Ukraine, France and Germany in February required both sides to withdraw heavy weapons from the line of contact. But international observers say those provisions have been routinely violated.
“Over the past week or two we’ve seen a great increase in [cease-fire] violations by the Russians and their agents in eastern Ukraine across the cease-fire line,” said John Herbst of the Washington-based Atlantic Council in an interview with VOA's Jeffrey Young.
“The Kremlin has put in, over the past couple of months, a substantial increase in advanced weaponry. So, they can move. They can thrust more deeply into Ukraine at any moment,” he said.
Russia analyst Keir Giles, who is with Chatham House in London, said Ukraine's president is right to be concerned about the recent events.
“President Poroshenko knows perfectly well that if he cries ‘wolf’ too often, people will stop paying attention. You have to assume that there is some genuine concern behind what seems to be a warning of imminent attack,” Giles said.
Giles said that the most recent flare-up in eastern Ukraine may not necessarily be the prelude to a Russian plan to create a “land bridge” connecting it to Crimea.
Herbst, a vocal proponent of providing lethal weapons to Ukraine to defend itself, said that the West’s response to the Ukraine crisis has been inadequate.
"We should be providing Ukraine with defensive weapons so they can defend their own territory. We should be putting much more, in the way of troops and military hardware into the Baltic States and Poland, and perhaps Romania, because Mr. Putin has designs on the eastern members of NATO,” said Herbst.