Violence flares in Ukraine, deepening crisis

Fresh violence erupted in eastern Ukraine Tuesday as thousands of pro-Russian protesters stormed key buildings, escalating the crisis after Moscow hit back at "Iron Curtain"-style Western sanctions.

A mob spearheaded by around 30 men carrying Kalashnikov assault rifles and grenade-launchers attacked the regional police headquarters in Lugansk, raising the heat in the worst East-West confrontation since the Cold War.

They had earlier seized the regional prosecutors' office, tearing down the Ukrainian flag and replacing it with that of Russia, which the West blames for stoking the violence in the ex-Soviet Republic.

More than a dozen towns and cities in the east have now fallen to pro-Russian rebels, who see the Western-backed leaders in Kiev as illegitimate "fascists" and want either independence or outright accession to Russia.

"It's good what the young people are doing. We don't want this Nazi junta that has seized power in Kiev. We don't recognise them. I want my children and grand-children to grow up in Russia," one retired engineer told AFP as he surveyed the violence in Lugansk.

As police failed to quell the violence and in some cases stood by, interim president Oleksandr Turchynov lashed out at what he called "inaction" and in some case "treachery" by law enforcement bodies on the ground.

He urged "Ukrainian patriots" in the region to sign up for police duty to counter the pro-Moscow insurgency that threatens to tear his country apart.

The latest unrest in Lugansk followed Monday's terrifying scenes in nearby Donetsk, where pro-Russian thugs armed with baseball bats, knives and fireworks attacked a pro-Ukrainian demonstration, wounding several in what Washington's ambassador to Ukraine called "terrorism, pure and simple".

As the situation on the ground descended further into chaos, the war of words between Moscow and the West continued, with Russia saying the United States was resorting to "Iron Curtain" policies with its new sanctions unveiled on Monday.

"Sanctions are always a boomerang which come back and painfully hit those who launch them," said Russian Deputy Prime Minister Dmitry Rogozin, according to the Interfax news agency on a visit to Crimea, which Russia annexed in March.

On a visit to Russia's Cold War ally Cuba, Foreign Minister Sergei Lavrov said the sanctions lacked "all common sense".

US moves to restrict high-tech exports to Russia appeared to cause particular fury, with Rogozin warning Washington was "exposing their astronauts on the ISS".

The International Space Station is operated jointly by Russia, the United States, Europe, Japan and Canada.

Astronauts and cosmonauts depend on Russian Soyuz rockets to ferry them between it and Earth, ever since NASA scrapped its space shuttles in 2011.

A Russian deputy foreign minister, Sergei Ryabkov, said in an interview with online newspaper Gazeta.ru that the US curb on high-tech exports was a "blow".

"This is a revival of a system created in 1949 when Western countries essentially lowered an 'Iron Curtain', cutting off supplies of high-tech goods to the USSR and other countries," he said.

Moscow also lashed out at the European Union for "doing Washington's bidding" as the bloc included General Valery Gerasimov, chief of the general staff of the Russian armed forces and the country's deputy defence minister, on a list of 15 Russians and Ukrainians targeted by an asset freeze and travel ban.

And it vowed that Japan's decision to deny visas for 23 Russian nationals "will not be left without a response".

The EU and Japanese blacklists are part of a G7 sanctions assault started by Washington on Monday with measures announced against seven Russian officials and 17 companies close to Russian President Vladimir Putin.

As the EU's top foreign policy official, Catherine Ashton, voiced alarm at "the downward spiral of violence and intimidation" in Ukraine, fears persisted of an imminent Russian invasion.

NATO said there were no indications that the tens of thousands of troops massed on the Ukrainian were pulling back, as announced by Russian Defence Minister Sergei Shoigu in a telephone conversation with his US counterpart Chuck Hagel.

Shoigu reiterated that Moscow had no plans to invade its neighbour and urged Washington to dial down its rhetoric over the crisis.

But Hagel called for an end to Russia's "destabilising influence inside Ukraine" and warned more pressure would be applied if it continued.

Hagel also asked for Moscow's help in securing the release of the seven OSCE inspectors held by pro-Russian militants in Slavyansk.

The local rebel leader in Slavyansk, Vyacheslav Ponomaryov, said "good progress" was being made in negotiations with the OSCE to free the men. But an OSCE negotiator gave a firm "no comment" to reporters.

The secretary general of the Organisation for Security and Cooperation in Europe, Lamberto Zannier, was in Kiev to supervise the tractions.

Kiev's soldiers are surrounding Slavyansk in a bid to prevent reinforcements reaching militants there.

The fresh Western sanctions are a response to Russia's perceived failure to implement an April 17 deal struck in Geneva to defuse the crisis by disarming militias and having them vacate occupied public buildings.

"Russia has so far failed to implement any part of the Geneva agreement," said British Foreign Secretary William Hague, who plans to visit Ukraine as well as Moldova and Georgia next week.

Among those targeted by the US sanctions is the president of Rosneft, Russia's top petroleum company and one of the world's largest publicly traded oil companies.

The EU said talks with Russia and Ukraine will take place in Warsaw Friday to try to resolve a $3.5-billion gas bill Gazprom calculates Kiev owes. Putin has threatened to cut off the gas flow to Ukraine if it is not quickly paid.

Ukraine and EU countries dependent on Russian gas, meanwhile, were worried Moscow's reprisals could hit the vital energy supply.

The crisis has accelerated since February, when Ukraine's Kremlin-backed president Viktor Yanukovych was forced to flee after months of increasingly bloody mass street protests by pro-Western demonstrators.