DONETSK, Ukraine — Seven European military officers and a translator being held hostage by pro-Russia separatists were paraded before the news media on Sunday, hours after another group of captives, three Ukrainian security agents, were shown on Russian TV huddled in a room, blindfolded and bloody.
Later in the day, pro-Russia activists took control of the state TV center in the regional capital of Donetsk without firing a shot. Members of a separatist movement called the Donetsk People's Republic, aided by a fight club from the eastern city of Kharkiv, stormed the broadcast facility.
The day's events showed eastern Ukraine slipping further into chaos, with armed separatists openly defying state authority and local police either folding in sympathy or admitting that they felt too intimidated to stop the pro-Russia groups.
As Moscow and Washington traded blame for a failure to halt the escalation in tension, diplomats moved to try to free the European military monitors.
Human rights observers say that as many as 24 people — journalists, activists, police officers, politicians and monitors — are being held in makeshift jails in Slovyansk, a city in the Donetsk region, in the heart of territory controlled by the separatists.
The Security Service of Ukraine said that three of its officers were captured by pro-Russia militants in the city of Horlivka, where the agents were investigating the recent torture and killing of a local politician and a university student. Both men were supporters of a unified Ukraine. Their bodies were found dumped in the river near Slovyansk.
In Slovyansk, hard-core separatists staged a news conference to display their captives, who were in Ukraine as part of a military observer mission operating under the auspices of the Organization for Security and Cooperation in Europe.
"We wish from the bottom of our hearts to go back to our homes," said one of the observers, German Army Col. Axel Schneider. The separatists labeled the captives "NATO spies."
German Foreign Minister Frank-Walter Steinmeier said the parading of the military officers before the news media was "a breach of all the rules." He appealed to Russia to pressure the separatists to free the monitors.
Late Sunday, one of the monitors, a Swede, was released because of a medical condition.