The Organisation for Security and Cooperation in Europe confirmed the release of the seven European military observers on its official Twitter feed.

Earlier Russian news agencies had quoted President Vladimir Putin’s special envoy as saying that “all the 12 people who are on my list have been freed”.

It wasn’t immediately clear why the envoy, Vladimir Lukin, spoke of 12 detainees.

The original team of monitors captured on April 25 comprised eight Europeans and five Ukrainians accompanying them.

One of the Ukrainians — thought to be the driver — was swiftly released.

Later, one of the Europeans, a Swede, was freed on medical grounds as he suffers from diabetes.

“This was a goodwill humanitarian act and we are very grateful to the masters of the city,” Lukin was quoted as saying.

“We would like this to be followed by other humanitarian acts including the cessation of gunfights,” he said, adding he was hoping the conflicting parties would also sit down at the negotiating table.

The release came a day after Ukraine’s army mounted an offensive on Slavyansk that claimed at least nine lives, including four servicemen.

The West has been pushing hard for the release of the men, with German Chancellor Angela Merkel saying on Friday it was an “important step” in de-escalating the crisis.

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