Pro-Russian separatists appear to be making preparations for a fresh offensive in eastern Ukraine, U.S. Defense Secretary Ashton Carter told lawmakers on Wednesday.

The Pentagon chief also said that sanctions imposed by European countries and a decline in oil prices were the most effective way to exert pressure on Russia over its role in the conflict.

Head of al-Mustaqbal Movement and former Prime Minister Saad Hariri met on Tuesday with French President Francois Hollande in Riyadh.

The meeting comes in light of Hariri's shuttle diplomacy to safeguard Lebanon from the conflict raging in the region.

Russia on Friday charged Ukrainian airforce officer Nadia Savchenko over the deaths of two Russian journalists in a politically charged case that has become emblematic of tensions between Kiev and Moscow.

The 33-year-old helicopter navigator is charged with acting as an accessory in the murder of two Russian journalists "with motives of political hatred."

Twenty-one foreign students were on Thursday in a critical condition in hospital after fire ripped through a student residence in Moscow, an official said.

The 16-storey dormitory, which belongs to one of Russia's top medical schools, caught fire late Wednesday, leaving a total of 43 people in need of medical attention.

Talks between the Syrian government and members of the tolerated opposition were set to end Thursday in Moscow with little sign of progress towards ending the spiraling conflict in the country.

Russian Foreign Minister Sergei Lavrov was due to open a final meeting between the two sides but opposition activists said there was little chance of a breakthrough after holding two days of talks with the delegation of Bashar Assad's regime.

Russian Deputy Foreign Minister Mikhail Bogdanov urged the Lebanese rivals to resolve the presidential deadlock to maintain stability, stressing that Moscow is seeking the election of a consensual president.

“This is the only solution,” Bogdanov was quoted as saying in comments published on Monday in local newspapers.

A Moscow-friendly Greece could paralyze NATO's ability to react to Russian aggression, former U.S. national security adviser Zbigniew Brzezinski warned Wednesday.

Athens could use its veto to slow the alliance's response if Russia set its sights on its Baltic member states, he told Poland's Dziennik Gazeta Prawna.

Russia and Cuba worked on their joint strategy against the U.S. economic embargo on the communist island Tuesday, during a visit by Moscow's Foreign Minister Sergei Lavrov.

Lavrov, the first Russian cabinet member to visit Cuba since Washington and Havana announced they would set aside their Cold War enmity and renew diplomatic ties, met President Raul Castro at the start of a four-country Latin American tour.

A deal that the Lebanese army had signed with Russia to buy anti-tank guided missiles and rocket launchers is facing an obstacle caused by the western sanctions imposed on Russia, As Safir daily reported on Tuesday.

The newspaper said that the agreement with Moscow to buy Kornet missiles and the long range rocket launchers faced technical and political problems because Lebanese authorities failed to transfer 38 million dollars to Russia.

British Prime Minister David Cameron is establishing a fund to help Eastern European states resist pressure from Russia, several media outlets reported on Friday.

Sky News said the "Good Governance Fund" would amount to £20 million ($30 million, 28 million euros) in 2015 and 2016.