Simon Ostrovsky, the U.S. journalist who was being held by pro-Russian gunmen in eastern Ukraine, is free and safe.

"Hostage @SimonOstrovsky is free and safe," Radio-Canada journalist Jean-François Bélanger tweeted on Thursday. "He is with us in CBC car en route to Donetsk."

Ostrovsky, a journalist for Vice News, had been covering the crisis in Ukraine for weeks and was reporting about groups of masked gunmen seizing government buildings in one eastern Ukrainian city after another when he was detained by pro-Russian gunmen for what they called "bad activities."

Vice News tweeted that it was "delighted to confirm that our colleague and friend @SimonOstrovsky has been released and is in good health."

Ostrovsky was captured at a checkpoint on Tuesday.

"They had my photograph. They pulled me out of the car and all hell broke loose," Ostrovsky told CBC News. "There were four other journalists with us in the car and I think they were released pretty early on."

Ostrovsky was held at a Ukrainian security service building in the eastern city of Slaviansk, where local pro-Russian forces have headquarters right now.

"They beat me up as an introduction to the whole situation, blindfolded me, tied my hands behind my back," Ostrovsky said. "Then they eventually untied them and I was just hanging out in the room with the other prisoners."

The CBC's Nahlah Ayed, reporting from Donetsk, said Bélanger was driving in a CBC car when he spotted the recently-released Ostrovsky walking along a street "with his belongings in a plastic bag."

Travelling in Slaviansk, Bélanger stopped, got Ostrovsky into the car, and headed toward Donetsk, about 125 kilometres away.

Stella Khorosheva, a spokeswoman for the pro-Russian insurgents in the eastern city of Slaviansk, confirmed Wednesday that Ostrovsky was being held at the local branch of the Ukrainian security service that was seized more than a week ago.

"He's with us. He's fine," Khorosheva told The Associated Press. When asked why Ostrovsky was being held captive, Khorosheva said he is "suspected of bad activities." She said the insurgents were holding Ostrovsky pending their own investigation.

"We had been looking into whether there were actual Russians involved in what’s going on here – for the two days prior to me being captured," Ostrovsky said. "I had been phoning them and requesting interviews with them on that subject so maybe that’s why they decided it was time to stop me."