Simon Ostrovsky
Vice journalist Simon Ostrovsky has been freed from detention in Eastern Ukraine.@SimonOstrovsky

Vice News journalist has been released from captivity in eastern Ukraine by pro-Russian militiamen.

The American reporter was taken hostage in the eastern Ukrainian city of Slaviansk and was held for three days before being freed by the insurgents.

On the subject of his release, Vice News said that the journalist was in good health following the detention.

"VICE News is delighted to confirm that our colleague and friend Simon Ostrovsky has been safely released and is in good health. We would like to thank everyone for their support during this difficult time. Out of respect for Simon and his family's privacy, we have no further statement at this time," the statement said.

Ostrovsky was held because he was "suspected of bad activities", according to pro-Russian spokeswoman for the rebels Stella Khorosheva.

Organisation for Security and Co-Operation in Europe representative on Freedom of the Media, Dunja Mijatovic expressed "deep concern" about his capture.

"I remain deeply concerned about the ongoing negative pattern in relation to journalists' safety in Ukraine," said Mijatovic.

The detention was announced by Vyacheslav Ponomarev, self-proclaimed "People's Mayor" of Sloviansk.

At the time of his kidnap, a Vice News statement said: "Vice is in contact with the US State Department and other appropriate government authorities to secure the safety and security of our friend and colleague, Simon Ostrovsky".

Ostrovsky is well-known for his on-the-ground reports from eastern Europe, notably his coverage of the escalating situation in Crimea earlier this year.