Ukraine's security service on Sunday opened a criminal probe into alleged attempts by individual politicians to seize state power, as mass protests against President Viktor Yanukovych raged in Kiev. An investigation has been opened "into the illegal actions by certain politicians aimed at the seizure of state power," a Ukrainian Security Service (SBU) spokeswoman told AFP. The politicians were not named but the probe appears to target opposition figures who have repeatedly called on Yanukovych to quit.