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The leaders of Russia, Ukraine, Germany and France are meeting in Belarus to try to stop the war in Ukraine. This comes amid the heaviest fighting yet in eastern Ukraine where Russian-backed rebels have been gaining ground in a fierce offensive. NPR's Corey Flintoff reports.

COREY FLINTOFF, BYLINE: In the days leading up to this meeting in Minsk, the Belarusian capitol, there was doubt that there would be any negotiation at all. Russian President Vladimir Putin said he would only go if the parties achieved agreement beforehand. The fact that he's taking part suggests that some sort of agreement will be reached, but analysts think it won't go much beyond an immediate framework for stopping the carnage - analyst Keith Darden.

KEITH DARDEN: There's going to be a cease-fire line, and there's going to be a withdrawal of forces to a significant distance away from that line.

FLINTOFF: In other words, each side would agree to pull its heavy weapons back out of range of its enemy. Darden is a professor at American University in Washington, D.C. He says Ukraine would like to push that line back to the positions that the two sides occupied in September when they agreed on a cease-fire that never really took hold. Fyodor Lukyanov is the editor of the Moscow journal, Russia in Global Affairs. He says the Russian-backed militias in eastern Ukraine have gained a lot of territory in the past few weeks. While it will be politically unpalatable for Ukrainian President Petro Poroshenko to acknowledge the loss of that territory...

FYODOR LUKYANOV: There is a pressure on the European side and maybe even on the American side - on Kiev to accept the reality.

FLINTOFF: The Minsk agreement that was signed back in September included some other provisions that, like the cease-fire, never fully went into force. One was that illegal armed groups and military equipment, fighters and mercenaries should be withdrawn from Ukraine. Ukraine, the United States and NATO all cite evidence that the biggest armed group in the region is the Russian army, although Russian officials continue to deny any military involvement.

Russia has said it wants Ukraine to recognize the two breakaway people's republics that separatists declared last spring. It also wants Ukraine to adopt a new constitution that will give a high degree of autonomy to those regions, a provision that would allow the pro-Russian separatists to veto Ukraine's entry into NATO or the European Union.

Fyodor Lukyanov says that even if he wanted to, Ukraine's president probably couldn't get those provisions through a hostile parliament in Kiev.

LUKYANOV: Poroshenko will fail to deliver what he committed to in Minsk - the special status and federalization of Ukraine. But it will be possible to avoid new military escalation because the conflict will be already frozen.

FLINTOFF: Lukyanov thinks a so-called frozen conflict may be the best Ukraine can hope for at this point. Keith Darden says the military alternative including the United States and other countries providing weapons to Ukraine would be a disaster. For one thing, Darden says, the threat of U.S. weapons could convince Russia to push harder before it loses the strategic advantage.

DARDEN: They could escalate. They could start to use airpower, and I think the use of airpower in combination with those ground forces would be absolutely devastating to the Ukrainian military.

FLINTOFF: Neither Darden nor Lukyanov think the current negotiations in Minsk will produce a lasting solution, but at this stage, just silencing the guns could be enough. Corey Flintoff, NPR News, Moscow. Transcript provided by NPR, Copyright NPR.