Russian authorities on Wednesday shut down a television channel serving Crimean Tatars, an ethnic group that opposed Moscow's seizure of Crimea, sparking concern in Ukraine and the West.

ATR television channel was forced off air after Russia's state media regulator refused to give it a broadcasting license. 

Russian authorities have barred a prominent Finnish investor from entering the country and accused him of espionage, the Scandinavian businessman said in interviews published Wednesday.

"Upon entering (Russia) on March 22 I was officially notified that I have been declared persona non-grata, under broad laws like being a security threats for the country," said Seppo Remes in an interview published by Russian newspaper Vedomosti.

Russia, moving ahead of a deadline for submitting pledges to tackle climate change, said Tuesday it could cut its greenhouse-gas emissions by up to 30 percent compared to 1990 levels, subject to conditions.

In a roster of commitments on the UN Framework Convention on Climate Change (UNFCCC) website, Russia announced that "limiting anthropogenic [man-made] greenhouse gases in Russia to 70-75% of 1990 levels by the year 2030 might be a long-term indicator."

The year-long conflict in east Ukraine has closed businesses across this industrial heartland, ramping up unemployment, crippling finances and leaving it ever more reliant on Moscow. 

Fierce fighting between government forces and pro-Russian rebels has ravaged a region that once provided 25 percent of the nation's exports and has shorn Kiev of a vital source of foreign currency, seeing the Ukrainian economy contract sharply. 

The U.S. abandoned late Tuesday a midnight deadline to agree the outlines of a nuclear deal with Iran but insisted that "enough progress" merited extending marathon talks into Wednesday.

"We've made enough progress in the last days to merit staying until Wednesday. There are several difficult issues still remaining," State Department spokeswoman Marie Harf said.

A top U.S. lawmaker in Kiev on Tuesday urged President Barack Obama to provide arms to Ukraine, calling its conflict with pro-Russian separatists "the most significant threat to peace...since the end of WWII."

William "Mac" Thornberry, Chairman of the House Committee on Armed Services, met with Ukrainian President Petro Poroshenko and said he hoped to convince Obama to heed a recent Congress vote overwhelmingly calling for the supply of defensive weapons.

All five suspects being held over the brazen murder of Russian opposition leader Boris Nemtsov have been charged with taking part in a contract killing, a Moscow court said Tuesday.

Moscow city court said in a statement that the accused -- all from Russia's volatile North Caucasus region -- had been charged with murder carried out for financial gain.

Syrian President Bashar Assad says he shares the same goals as Iran and Russia when it comes to the brutal war tearing apart his country.

Assad, speaking on PBS television in excerpts of an interview airing Monday, insisted that close allies Russia and Iran "want to have balance in the world."

Lithuania on Monday alleged that one-third of Russian diplomats in the EU and NATO Baltic state were working for spy agencies, and warned that Moscow could test the alliance with unconventional tactics.

Lithuania's intelligence agency said it kicked out three Russian spies last year, adding that Moscow was increasingly interested in the NATO member's military infrastructure.

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.