Ukraine crisis: Putin asserts Russia's 'right' to invade country during live-phone

Vladimir Putin has asserted Russia’s “right” to invade Ukraine during a live phone-in, after accusing it of plunging Kiev into an “abyss” following a night of bloodshed in the east.

“I remind you that the Federation Council has given the president the right to use armed forces in Ukraine,” he said, referring to the upper house of Parliament during the annual televised question and answer session The Direct Line with Putin.

“I really hope that I do not have to exercise this right and that by political and diplomatic means we will be able to solve all of the sharp problems.”

Mr Putin said Russia has not ruled out sending troops into eastern Ukraine - but said he remained hopeful diplomacy would instead resolve the crisis.

The Russian leader argued the country had been forced to respond to Nato enlargement and that its annexation of Crimea was partly influenced by the Western military alliance's expansion into eastern Europe.

He said: "Our decision on Crimea was partly due to ... considerations that if we do nothing, then at some point, guided by the same principles, NATO will drag Ukraine in and they will say: 'It doesn't have anything to do with you.'"

"I hope that they are able to realise what a pit, what an abyss the current authorities are in and dragging the country into," Mr Putin continued while dismissing accusations that Russian agents were acting in east Ukraine as "rubbish".

Ukraine's Berkut riot police, a force disbanded by authorities in Kiev after being blamed for the deaths of protesters, had served honourably in the line of duty, he told the phone-in.

Overnight, three pro-Russian separatists have been killed and thirteen more injured in the bloodiest attack in eastern Ukraine since the crisis began.

The bloodshed came after gunfire was exchanged between Ukraine forces and pro-Russian militants during an attack on a National Guard base in the Black Sea port of Mariupol.

This morning, Ukraine's state security service said it is detaining 10 Russian citizens, all of whom have intelligence backgrounds.

On Wednesday, pro- Russian troops seized six military vehicles and disarmed Ukrainian troops in a somewhat humiliating defeat for the interim government’s “anti-terrorist programme”.

Some troops attempting to reclaim captured sites in over a dozen towns and cities were sent home on buses in Kramatorsk, while pro-Moscow demonstrators took over yet another site, the mayor's office at Donetsk, after holding the administrative building in the city for weeks.

But overnight, 300 pro-Russian separatists threw Molotov cocktails and opened fire on a military unit in Mariupol, the Interior Minister said this morning.

Arsen Avakov said in a post on Facebook that an armed group of about 300 attacked the base in Mariupol on the Sea of Azov with guns and petrol bombs. National Guard members first fired warning shots but then opened fire as the attack continued.

Sixty-three people have been arrested and most of the attackers disarmed, Mr Avakov said.

"According to preliminary data, three attackers were killed, 13 wounded and 63 detained," his statement read.

The Ukrainian government said that "given the aggressive nature of the attack on the base”, it is continuing to send in helicopters despite the military operation’s lack of success thus far.

The latest unrest comes ahead of crunch talks in Geneva today between Ukraine, the US the European Union and Russia, who are meeting all together for the first time since former president Viktor Yanukovych was ousted in February.

The US has threatened further sanctions in the wake of escalating tensions in the country, with President Barack Obama sending a direct warning to the Mr Putin that his actions all face consequences.

"Each time Russia takes these kinds of steps that are designed to destabilize Ukraine and violate their sovereignty, there are going to be consequences," Mr Obama said Wednesday in an interview with CBS News.

"Mr. Putin's decisions aren't just bad for Ukraine. Over the long term, they're going to be bad for Russia."