Ukraine says rebels violated the ceasefire six times between Monday and Tuesday.
The economic crisis has been particularly felt in Donetsk, where goods are scarce and prices have soared.
Iran must commit to a verifiable freeze of at least 10 years on sensitive nuclear activity for a landmark deal to be reached, but the odds are still against sealing an agreement, Obama told Reuters, an exclusive report says.
Cameras were either turned off or failed to capture relevant footage when Russian opposition leader Boris Nemtsov was killed, reports say.
Romania relies almost entirely on Russian gas imports through Ukraine and a shutoff there would have a domino effect.
Some of the ships, like Russia's latest nuclear submarines, are new. Others are to be refurbished and upgraded.
Anna Duritskaya, 23, is purported to be the lone witness to the Russian opposition leader's killing.
A gas dispute is becoming increasingly contentious ahead of planned talks around Europe over the crisis in Ukraine.
Inna Duritskaya also claimed that Russian President Vladimir Putin is trying to link the murder to the conflict in eastern Ukraine.
Last week, Kerry had accused Russia of lying about its role in the conflict in eastern Ukraine, which has so far claimed 6,000 lives.
Marchers blame Kremlin for the shooting death of the opposition leader.
The former Soviet country is likely to release official results Monday.
The opposition politician was shot four times as he walked in Moscow.
The event will replace a planned protest march Nemtsov had supported before he was shot and killed Friday.
Ukrainian President Petro Poroshenko said in televised remarks Saturday Boris Nemtsov told him he had proof of Russia's role in the Ukraine conflict and would reveal it.
The U.S. government called for a prompt investigation into the killing of opposition leader Boris Nemtsov, who was shot dead in Moscow on Friday.
Boris Nemtsov had been due to lead a mass rally against Putin and the war in Ukraine this Sunday.
An unidentified attacker shot Nemtsov, 55, four times while he was walking near the Kremlin.
The payment gets Ukraine enough of a natural-gas supply from its contentious neighbor to meet demand for only a few days.
Four militants were involved in the jailbreak, but only two got away. One was shot dead and the other was recaptured.
Copenhagen police only described the alleged accomplice as a "young man" and didn't disclose his name for legal reasons.
Russia is moving ahead with the "creeping annexation" of two breakaway Georgian regions as part of an aggressive strategy to broaden its influence in the region, Georgia's foreign minister said Thursday.