A Russian court on Friday convicted four men for helping orchestrate twin suicide blasts in 2013 that killed 34 people, handing down sentences of up to 19 years in detention.

The attacks against the main railway station in the southern city of Volgograd and a trolleybus took place on two consecutive days in late December, sparking security fears only two months before Russia hosted the Winter Olympic Games.

The European Court of Human Rights Thursday ordered Russia to pay more than 50,000 euros' ($61,552) compensation to two opposition leaders jailed for demonstrating against what they said were rigged elections.

Popular blogger and activist Alexei Navalny and Solidarnosc movement leader Ilya Yashin were jailed for 15 days after the December 5th, 2011 demonstration in Moscow.

President Vladimir Putin on Thursday accused the West of exploiting the Ukraine crisis to undermine an increasingly confident Russia, and said Crimea was "sacred" to Moscow.

In his annual state-of-the-nation address, Putin said Russia was justified in its stance on Ukraine but that Moscow would not sever ties with the West despite confrontation with Brussels and Washington.

Russian President Vladimir Putin urged the central bank and government on Thursday to take 'tough action' to stop speculation on the ruble after the currency hit new all-time lows this week.

"I ask the Bank of Russia and the government to carry out tough coordinated actions to discourage the so-called speculators from trading on the fluctuations of the Russian currency," he said during his annual state of the nation speech in Moscow.

U.S. Secretary of State John Kerry urged Russia Thursday not to isolate itself "through its own actions" as top diplomats grappled with elusive peace efforts in Ukraine but Moscow lashed out at biting sanctions.

President Vladimir Putin accused the West of using the Ukraine conflict as a pretext to restrain a muscular Russia with sanctions and defiantly declared that Moscow would overcome the blow to an economy on the brink of recession.

The Ukraine military reported Thursday more than 70 rebel attacks on its positions in the past 24 hours.

The attacks took place across several parts of the frontline in eastern Ukraine, a military spokesman said, including in Lugansk and the airport in Donetsk, where the two sides have this week tried to put ceasefires in place.

Russian deputy Foreign Minister Mikhail Bogdanov is seeking to end the political deadlock in Lebanon and the rift between the Lebanese arch-foes during his visit to Beirut, Russian Ambassador to Lebanon Alexander Zasypkin said on Thursday.

President Barack Obama said Wednesday Russian counterpart Vladimir Putin is unlikely to shift his stance on Ukraine until the full force of economic sanctions levelled against Moscow hits home.

Obama said Putin's "nationalist, backward-looking" outlook had isolated Russia internationally but had played well domestically. 

NATO said Wednesday it will keep military channels of communication with Russia open to avoid any misunderstandings over military activity, as the Ukraine crisis stokes tensions not seen since the Cold War.

The 28 member states of the U.S.-led alliance, set up originally to protect Western Europe from the Soviet Union, "agreed that at this time of tension there is a need for continued communications among NATO and Russian military to avoid any incidents," a NATO press officer said.

Moscow is ready to host a conference on ridding the Middle East of weapons of mass destruction, Foreign Minister Sergei Lavrov said in Sudan on Wednesday.

"There should be a conference to remove weapons of mass destruction and put in place an agreement to make the Middle East a region free of nuclear weapons," Lavrov said before attending a forum on cooperation between Russia and the Arab League.