Suddenly, the situation in eastern Ukraine is looking scarier than ever. Fierce fighting has escalated around the city of Donetsk, whose airport now lies in ruins. Rather than skirmishing with separatist groups, Ukraine says its army is now engaged in direct combat with Russian troops, including some 2,000 Russian soldiers and 200 tanks and personnel carriers that have crossed the border in recent days.
At the same time, unidentified attackers have staged bombings in cities outside the main combat zone, raising the prospect that a new, broader campaign of civilian terror may be under way. Thirteen people were injured in a Jan. 19 bomb attack in Kharkiv, Ukraine's second-largest city, which is in the eastern part of the country but has largely escaped fighting until now. "The situation is getting worse," President Petro Poroshenko told reporters on Wednesday before he cut short his visit to the World Economic Forum in Davos, citing "grave danger" at home. (Russia, as it has in the past, dismissed reports of Russian military involvement as "nonsense.")
For months now, it's looked as if the situation was becoming a sort of stalemate, with sporadic outbursts of fighting but neither side clearly prevailing. Why is it reigniting now?
One simple answer could be that Russians and Ukrainians alike took a break from fighting over the Orthodox Christmas and New Year holidays, which span about two weeks from late December until almost mid-January. There's also the possibility that the pro-Russian side is trying to strengthen its position ahead of peace talks scheduled this week in Berlin.
A more ominous possibility is that pro-Russian separatists, with backing from President Vladimir Putin, are now trying to enlarge the territory they control, says Joerg Forbrig, program director with the German Marshall Fund of the U.S. in Berlin. "They may try to get hold of the [Black Sea] port of Mariupol, and possibly create a land bridge to Crimea in the medium term," he says. Crimea's geographic isolation from Russia has spurred shortages of consumer goods and inflation since the peninsula's annexation by Moscow last year.
As for the attacks on Kharkiv and other cities outside the main combat areas, Forbrig says Moscow may be trying to sow doubts among local citizens "about the ability of the Ukrainian security apparatus and police to protect them."
"Russia is using all possible means to destabilize Ukraine militarily and economically," he says. "It's almost natural that there would be terrorist attacks to destabilize the country."
At least for now, Moscow seems to face little immediate risk of additional Western sanctions. European Union foreign ministers this week said they would maintain existing sanctions but planned no additional measures. Both the EU and the U.S. have been working behind the scenes on efforts to start mending relations with the Kremlin.
