Military observers kept prisoner in Ukraine for more than a week have been released as bloody clashes in the country show no sign of letting up.
The seven observers and their five assistants, from the Organisation for Security and Cooperation in Europe, were seized in Slavyansk on April 25.
The separatists had previously accused the observers of being "Nato spies" and said they were to be used as human shields.
A prisoner-swap was thought likely, although they were set free today without any conditions.
Two of the observers pictured while they were being held in SlavyanskColonel Axel Schneider, the head of the observers, said the group had shown "strength" and said the captivity was "unforgettable for us".
The release comes as Ukraine launched a dawn military operation against separatists in the east of the country.
Interior Minister Arsen Avakov said troops had seized control of a television tower in Kramatorsk, near the rebel stronghold of Slavyansk.
Fresh scuffles broke out outside the burned building in Odessa on Saturday"We are not stopping," Mr Avakov wrote on his Facebook page. Heavy fighting is now being reported in the town, according to Ukraine's anti-terrorist centre.
The violence comes hours after 31 people died after a building in Odessa was set on fire during clashes between protesters.
Police said some people inside the trade union building were overcome by smoke and others were killed jumping from windows as they tried to escape.
A pro-Russian activist fires a gun during clashes with rivalsPro-Russian and pro-Kiev activists fought running battles as the southern port city saw some of its worst violence since President Victor Yanukovych was ousted in February.
The Interior Ministry said a total of 42 people were killed in Odessa.
Russia said it was "outraged" and denounced the "criminal irresponsibility" of the pro-Western authorities in Kiev.
Russia's foreign ministry called on Ukraine and its "Western backers to end the anarchy and take responsibility for the Ukranian people".
At an emergency session of the United Nations Security Council, the UK accused Moscow of "breathtaking" hypocrisy over the latest clashes.
A protester throws a petrol bomb at the trade union building in OdessaThe UK's ambassador to the UN, Sir Mark Lyall Grant, said Russia had "funded, equipped and directed" some of those involved in the insurgency.
"Many" pro-Russian separatists were also said to have been killed on Friday as the Ukrainian army took control of checkpoints around Slavyansk.
Two Ukrainian soldiers were also killed as two helicopters were shot down in the city, acting president Oleksandr Turchynov said.
People wait for rescue on an upper-storey ledge during the fireThe Ukrainian Security Service said one was shot down with a surface-to-air missile, adding that the sophisticated weapon undermined Russia's claims that Slavyansk was simply under the control of armed locals.
Sky News Chief Correspondent Stuart Ramsay, in Donetsk, said the Ukraine government is in a "very difficult position".
"If they want to take control of these towns they are going to have to put a lot of soldiers on the ground and bring in police from other parts of the country. If that happens it will absolutely be violent – it will only escalate further.
"Russia has made it clear that would be a reason for them to intervene to protect ethnic Russians.
"If Kiev doesn't do that, they are going to see the eastern parts of the country drift away."
Russia has tens of thousands of troops near Ukraine's border, and Kiev claims its neighbouring country is preparing to invade and that it is stoking the unrest in the east.
Moscow denies the allegations, but has warned Russia would respond to attacks on Russian citizens or interests in the east, where insurgents have seized government buildings in around a dozen cities.