Pro-Russian separatists in eastern Ukraine have freed a group of European monitors who were taken captive in the flashpoint town of Slovyansk more than a week ago.
The separatists freed the seven international observers and their five Ukrainian assistants on Saturday.
According to news organizations, an insurgent leader said he ordered their release because of increasing insecurity in the city.
The team was acting under the authority of a four-party agreement directing the Vienna-based Organization for Security and Cooperation in Europe - OSCE - to monitor security and human rights in Ukraine's Russian-speaking east and south. Separatists seized the group, claiming some members were spies.
Also, Ukrainian forces have moved into Kramatorsk, a town about 17 kilometers from Slovyansk. An intelligence official said Saturday that government forces had regained control of a TV and radio facility in the eastern town.
Pro-Russian gunmen have seized control a number of key facilities in eastern Ukraine. They have declared a May 11 referendum on whether to secede from Ukraine and join Russia.
In another development Saturday, the interim government declared at least two days of mourning in the port city of Odessa where clashes Friday between pro-Russian separatists and supporters of the central government in Kyiv resulted in at least 42 deaths.
Most of the people died in a building fire that broke out during the fighting. Odessa, a key Black Sea port, had escaped most violence gripping large parts of eastern Ukraine.
In Moscow, a spokesman for Russian President Putin called a Ukrainian offensive under way in Slovyansk "a criminal act." He also said it had "effectively destroyed the last hope" for implementing an April 17 international accord aimed at defusing the crisis.
Mr. Putin on Thursday demanded that Ukraine withdraw all military personnel from the troubled region near the Russian border.
In Washington, U.S. President Barack Obama -- speaking alongside German Chancellor Angela Merkel -- said that if Russia's leadership continues to destabilize eastern Ukraine, the U.S. and European Union will move quickly to impose additional penalties, including both diplomatic and economic sanctions.