Fears are growing for a team of international observers captured by pro-Russian rebels. The militants declared Saturday the group would only be freed in exchange for the release of prisoners held in Kiev. Moscow says it will do all it can to help with the release. But Kiev blames Russia for the kidnapping, saying the hostages are being used as human shields. This as Ukrainian armed forces launched the second phase of its operation to regain control of the town of Slavyansk. CCTV’s Kate Parkinson has more.

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International Observers Captured by Pro-Russian Rebels

Fears are growing for a team of international observers captured by pro-Russian rebels. The militants declared Saturday the group would only be freed in exchange for the release of prisoners held in Kiev. Moscow says it will do all it can to help with the release. But Kiev blames Russia for the kidnapping, saying the hostages are being used as human shields. This as Ukrainian armed forces launched the second phase of its operation to regain control of the town of Slavyansk. CCTV's Kate Parkinson has more.

Ukrainian armed forces were flexing their military muscle around the most militant of towns in eastern Ukraine on Saturday.

Helicopters roared overhead and armored personal carriers patrolled the area but they did not enter Slavyansk.

The second phase of Kiev’s operation to regain control of the region involves mounting a blockade around the occupied city.

In the center there was an air of normality as activists registered people to form a new local council to replace the previous administration ousted from office when gunmen took over the council building.

But life in Slavyansk isn’t normal. A group of international observers are currently being held by anti-government gunmen-the monitors are part of a German-led military verification mission.

A leader of the anti-government forces said the foreign military observers are being held here in Slavyansk, possibly in this building right behind me, he said they could be released but only in exchange for some of their prisoners.