Ukrainian opposition leader Vitali Klitschko has appealed to his supporters to go on a brief "warning strike" on Thursday, in a show of strength and unity amid a planned round of negotiations with government officials.
The opposition was also preparing to stage a nationwide strike, Klitschko said, Ukraine's Pravda reported.
Opposition leaders — who also met Wednesday with President Viktor Yanukovych — were set to continue talks aimed at resolving the months-long crisis that has turned increasingly violent in recent days, and Klitschko called for a brief "warning strike" to accompany the negotiations.
"Go out for a half hour or an hour, if you have a chance," Klitschko said. "Go out to government offices, show your views, your resistance, your peaceful resistance."
"Call your friends on the phone, it is important to show [resistance] to the authorities," he said.
Ukraine's Prosecutor General Viktor Pshonka issued a statement earlier this week calling the protests in Kiev "crimes against the state."
Prime Minister Mykola Azarov has warned that the government may have to use anti-protest laws that came into force on Wednesday against the demonstrators. The laws make blockading public buildings punishable by up to five years in prison.
Protesters said the government also appeared to have adopted a new tactic to quell the demonstrations, by sending text messages that warned cell-phone users that security forces have them nailed as suspected rioters.
"Dear subscriber, you are registered as a participant in a mass riot," the text messages reported by cell-phone users near the scene of violent clashes earlier this week.