EU foreign ministers will consider further "robust measures" against Russia over the fighting in Ukraine when they meet in Brussels Thursday, Ukrainian foreign minister Pavlo Klimkin said.

His European counterparts are holding emergency talks on new sanctions after dozens of people were killed in clashes between Ukrainian forces and Moscow-backed rebels near the key port city of Mariupol.

A mother of seven has been accused of treason for calling the Ukrainian embassy about Russian troop movements in the latest sign of Moscow attempting to cover up its intervention in its neighboring state.

Svetlana Davydova, 36, was arrested last week by a group of men in black uniforms who burst into her apartment in the town of Vyazma, west of Moscow, her husband Anatoly Gorlov told AFP.

The last Soviet leader Mikhail Gorbachev on Friday accused the United States of drawing Russia into a new Cold War and said he feared hostilities could escalate into armed conflict.

The United States "has already drawn us into a new Cold War, trying openly to achieve its main idea of triumphalism," Gorbachev said in an interview with the Interfax news agency.

The United States gave a clear signal Wednesday that Russia will face further sanctions for what the White House says is Moscow's role in fueling violence in eastern Ukraine.

Following a telephone call between U.S. Vice President Joe Biden and Ukrainian President Petro Poroshenko, the White House condemned "Russian-backed separatists" and the "heavy toll that the Russian-backed offensive in the east was having on Ukraine's civilian population."

The White House said Wednesday it was "monitoring closely" events in Greece, where a new hard-left government has vowed to reopen the terms of a massive financial bailout and stated opposition to more sanctions against Russia.

U.S. President Barack Obama rang Prime Minister Alexis Tsipras to congratulate him on his recent election victory, a win that has put Athens on a potential collision course with its European neighbors and with Washington.

Lithuania's defense ministry on Wednesday began distributing wartime survival manuals to schools around the country  reflecting anxiety in the Baltic state over events in Ukraine.

The 98-page guide offers practical advice for emergency and wartime situations from setting up basement shelters to handling hostage dramas to evacuating from war zones. 

Russia's Supreme Court on Wednesday dismissed the government's bid to shut down a leading human rights group, a rare victory for harried civil society in the country.

Judge Alla Nazarova rejected a lawsuit from Russia's justice ministry to dissolve the Memorial group -- which rose to prominence exposing Soviet-era repression -- that claimed the group had violated its charter.

Ukrainian President Petro Poroshenko said on Wednesday he had written a letter to Russia's Vladimir Putin demanding that Moscow rein in eastern separatist fighters in his war-torn ex-Soviet republic.

Poroshenko said his letter also requested that Russia release female Ukrainian pilot Nadia Savchenko, who claims she was abducted by pro-Russian fighters before being put in a Moscow prison and starting a hunger strike.

Syrian opposition figures and representatives of the regime of President Bashar Assad began talks in Moscow Wednesday but there was little hope that they would make a breakthrough in ending the country's brutal war.

The talks between opposition groups tolerated by Damascus and a Syrian delegation led by ambassador to the United Nations Bashar Jaafari came as Kurdish forces battled the Islamic State group around Kobane, after expelling them from the strategic town on the Turkish border.

The Kremlin on Wednesday confirmed that North Korean leader Kim Jong-Un will attend World War II ceremonies in Moscow in May, in what would be his first foreign trip since taking power in 2011.

"The participation of the North Korean leader has been confirmed, we are preparing for his arrival," President Vladimir Putin's spokesman Dmitry Peskov told the Interfax news agency.