Pro-Russian separatists fire into the air during a laying of the capsule ceremony for the chapel to be built in memory of rebels and civilians who were killed in eastern Ukraine at a destroyed war memorial at Savur-Mohyla, a hill east of the city of Donetsk, on Dec. 7, 2014. Reuters/Maxim Shemetov

Diplomatic hopes of a breakthrough over the war in Ukraine were dealt a fresh blow after a summit planned to bring lasting peace to the region was suspended. The failure to make progress leaves eastern Ukraine in a state of flux and raises questions about how the collapse will translate to the war on the front lines.

“I think the breakdown of the talks means we can expect to see the situation get worse, although we don’t know how much worse just yet,” said Chris Chivvis, associate director of the International Security and Defense Policy Center and a senior political scientist at the RAND Corporation, a Washington, D.C.-based think tank. “The nature of a conflict is that you’re never really sure if you’re going to get an event that really inflames things and have them spiral out of control.”

The meeting among French, German, Russian and Ukrainian leaders that was supposed to take place in Astana, Kazakhstan, Thursday was canceled after a meeting of foreign ministers in Berlin Monday determined that not enough progress had been made to justify the summit.

Despite relative calm over the Eastern Orthodox holiday period, the Berlin talks came amid a surge of violence across the region that saw pro-Russian forces come within 400 meters of the Ukrainian-held Donetsk airport. Separatist forces offered the Ukrainian military until 5 p.m., local time, to vacate the airport or face being “destroyed.” The deadline came and went as Ukrainian artillery units quelled the separatist’s advance, according to the Ukrainian Independent Information Agency. Local media also reported that 10 people had died and 13 were injured after a shell hit a bus at a checkpoint in Donetsk.

The collapse of the talks, according to Ariel Cohen, director of the Center for Energy, National Resources and Geopolitics at the Institute for Analysis of Global Security, have further undermined September’s ceasefire, which has been more or less ignored in the Donbass region, especially in and around Donetsk airport, where fighting has relentlessly continued.

“It’s a matter of political power,” Cohen said. “It’s up to the Russian leadership to bring this conflict to a close. And as the economic situation in Russia deteriorates, the chances are increasing that Russia may reconsider.”

Indeed, Russia’s economy teeters on the brink of recession, largely because the collapse of global oil prices has devastated the federation’s budget. The dip of the price of oil to below $50 per barrel over the past week from above $100 per barrel at the beginning of 2014 represents a reduction of about a third of the Russian budget. While Russia would ordinarily be able to rely on international financial mechanisms to prop up its budget and overall economy, sanctions against the country have left it with few places to turn for help.

Chivvis believes that the economic situation in Russia is still the best chance for peace in Ukraine. “I think it is unfortunate that the talks have broken down, but that will only increase the pressure Russia is feeling because of declining oil prices,” he said. “It will offer some additional leverage that’s been lacking to try and push through a deal, but I don’t know what plans there are to have another go at talks.”

U.S. Air Force Gen. Philip Breedlove, NATO's supreme commander in Europe, said at a press conference in Poland on Monday that Russia was still training pro-Russian forces and continuing to offer support. “What there was not a lull in is the continued resupply, continued training and continued organization of forces east of the line of contact,” he said, referring to the demarcation line that separated Ukrainian and rebel forces.

A major assault by pro-Russian forces on Donetsk airport Tuesday saw the air traffic control tower, a symbol of Ukrainian resistance, collapse. According to the Ukrainian Independent Information Agency, rebel forces attacked the airport from two sides with tank and artillery fire.