A Russian nuclear scientist has been charged with disclosing state secrets and faces up to four years in prison over an article he published in a Czech journal, his lawyer said Wednesday.

Vladimir Golubev, a former employee of the country's top nuclear weapons research and development center, is accused by the security services of disclosing state secrets after publishing an article about explosives in a Czech journal, his lawyer told AFP.

Greece's new government remains committed to its NATO role despite close ties with Russia that have worried its allies, Defense Minister Panos Kammenos told AFP on Wednesday.

Speaking after his first meeting with NATO Secretary General Jens Stoltenberg and on the eve of a gathering of the alliance's defense ministers, Kammenos played down concerns that Athens could go soft on Russia over the crisis in Ukraine.

France has no plans to supply weapons to Ukraine to tackle the pro-Russian insurgency in the east of the country, Defense Minister Jean-Yves Le Drian said Wednesday.

"We have no intention of supplying lethal weapons at this time," Le Drian said, responding to a mounting debate triggered by reports that the United States is considering arming the Ukrainian government.

With pro-Russians and ex-Communists in the cabinet, Greece's new hard-left government has sparked concerns of a strategic shift towards Moscow -- but Athens has its eyes firmly on Europe, experts say.

The main governing Syriza party no longer advocates Greece leaving NATO, but Foreign Minister Nikos Kotzias has highlighted the country's historic ties with Russia and condemned the EU's "spasmodic" approach to Moscow.

A mother of seven accused of treason for telling the Ukrainian embassy about Russian troop movements was to be released from jail Tuesday, her husband said, though the charges against her remain.

Svetlana Davydova, who faces between 12 and 20 years in prison, is being held in the high-security Lefortovo jail in Moscow. 

Fears grew Tuesday of an escalation in the mounting bloodshed in east Ukraine as the United States mulled arming Kiev and pro-Russian rebels ordered a mass mobilization.

At least 16 civilians and five government troops were killed over the past 24 hours in fierce clashes across the conflict zone, government and pro-Russian rebel officials said.

Two Russian men working as U.N. contractors in Sudan have been kidnapped in the country's Darfur region, officials said on Tuesday.

The men were employees of UTair, one of Russia's largest airlines, and were in Sudan on a contract for the U.N. mission in the country, UNAMID, the company said in a statement.

A mass call-up Monday by separatist authorities aimed at boosting their forces in east Ukraine to 100,000 fighters sparked mixed reactions from inhabitants in rebel bastion Donetsk.

While some met the call-to-arms -- which the pro-Russian rebels said was voluntary -- with jingoistic fervor, others who spoke to Agence France-Presse dismissed the plan as fantastical or said they had no intention of signing up.

Russian conscripts are coming under new pressure to sign up as professional soldiers and fear being dispatched to fight in Ukraine alongside Moscow-backed separatists, rights activists said Monday.

Activists sounded the alarm after a new spike in complaints from recruits doing compulsory military service and their families, as peace talks have broken down and fresh fighting is erupting in eastern Ukraine.

Chinese President Xi Jinping on Monday hailed his country's relations with India and Russia as Beijing looks to increase its heft on the global diplomatic stage.

Twin visits by New Delhi's foreign minister Sushma Swaraj and Sergei Lavrov from Moscow come on the heels of a high-profile trip to India by U.S. President Barack Obama last week, and with Russian leader Vladimir Putin globally isolated over the conflict in Ukraine.