A Russian military court on Tuesday sentenced a Ukrainian filmmaker to 20 years in a strict-regime prison colony on terror charges in a trial condemned by Kiev, Western rights groups and top film directors.

Oleg Sentsov, 39, was convicted for allegedly carrying out arson attacks on pro-Kremlin party offices in Crimea after it was seized by Russia last March, and plotting further attacks, including blowing up a Lenin statue in the peninsula's main city of Simferopol.

Ukraine and pro-Russian rebels on Tuesday reported the deaths of five people in clashes in the east that raged despite a new EU push to end one of Europe's bloodiest conflicts in decades.

A spokesman for the army in Kiev said four servicemen were killed and 12 injured in mortar fire exchanges across the eastern separatist province of Donetsk.

Ukraine and its biggest lenders appeared to be making cautious but steady progress Tuesday toward a debt restructuring deal that would save the war-torn country from hurtling into default.

The Wall Street Journal reported Monday that a group of commercial creditors holding nearly half of the $19 billion (16.5 billion euros) in debt under negotiation have offered to take a 20 percent write-down on the face value of their bonds.

The United States soon will deploy F-22 Raptors in Europe, sending the stealth fighter jets to reassure NATO partners concerned about Russia's actions in Ukraine, a Pentagon official said Monday.

Air Force Secretary Deborah Lee James did not offer specifics about where or when the single-seat jets would be deployed, citing operational security reasons. James also would not say how many of the planes would be deployed.

Ukrainian President Petro Poroshenko on Monday accused Russia of sending major military backup to pro-Moscow rebels, speaking just ahead of talks on the conflict with German Chancellor Angela Merkel and French President Francois Hollande.

"Just this week three big convoys crossed our border towards Lugansk, Donetsk and Debaltseve," Poroshenko said, referring to rebel-controlled areas of eastern Ukraine.

European Commission chief Jean Claude Juncker will hold talks in Brussels next week with Ukrainian President Petro Poroshenko about the tattered ceasefire in eastern Ukraine, the EU said Friday.

Juncker will meet with Poroshenko next Thursday to discuss "implementation of the Minsk agreement," Commission spokeswoman Annika Breidthardt told reporters.

A Russian court on Friday turned down an appeal to shift the high-profile trial of a Ukrainian female helicopter pilot from southern Russia to Moscow, her lawyer said. 

Nadiya Savchenko, 34, went on trial last month in a provincial court close to the Ukrainian border for her alleged involvement in the killing of two Russian journalists in war-torn eastern Ukraine last year.  

Kiev on Thursday said four soldiers had been killed and 14 injured in renewed clashes with pro-Russian insurgents in the former Soviet country's separatist east.

Military spokesman Oleksandr Motuzyanyk told reporters that the losses came in Lugansk -- the smaller of the two separatist provinces in Ukraine to have fallen under partial militia control in the past 16 months of conflict.

Germany said Wednesday it could not rule out Russian President Vladimir Putin would take part in a future round of talks over conflict-torn eastern Ukraine after speculation that Western leaders were snubbing him.

Chancellor Angela Merkel is hosting talks with France's President Francois Hollande and Ukrainian leader Petro Poroshenko on Monday, and analysts said the conspicuous absence of Putin underlined that relations were deteriorating as new violence flares in eastern Ukraine.

The OSCE on Wednesday accused rebels controlling parts of east Ukraine of barring access to their monitors, as fears grew that escalating violence could flare up into a return of all-out war.

"They deny us access to specific areas. We are not allowed through at checkpoints," Alexander Hug, the deputy chief of the OSCE's monitoring mission in eastern Ukraine, told Germany's Die Welt newspaper.