One of about 30 protesters is reported to have died in eastern Ukraine after police broke up their tent city.
The group were survivors of the Chornobyl nuclear accident and had been staging a hunger strike in Donetsk since November 14 against cuts in their state pensions.
A court ruled their protest illegal last week, and police moved in late on November 27 to evict them from their tent camp.
The protest leader said police seized a power generator, a stove, and cut off lighting.
Nikolai Goncharov said a 68-year-protester fell ill during the police operation and died as he was being rushed to hospital in an ambulance.
One protester, Volodymyr Derkach, voiced outrage over the incident.
"What happening here, guys?! What happening in this country called Ukraine?" Derkach said. "They killed the man! They killed! Why did they kill him?!"
Goncharov denounced the police action as an "act of terrorism."
There has been no comment yet from the police on the protester's death.
compiled from agency reports