Wednesday has seen a tense stand-off in the Ukrainian capital Kyiv.
Amid more sporadic clashes, police massed on the edge of Maidan Square threw stun grenades and used water cannon to try to disperse protesters, who threw their own missiles.
Many among the opposition feared nightfall would bring another crackdown by the security forces, following Tuesday’s violence which left at least 25 dead.
The capital has been on virtual shutdown, with the metro closed and main roads blocked by police.
Ukraine’s security services have qualified an earlier statement about a nationwide “anti-terrorist” operation, now saying it’s being planned but hasn’t been launched.
The intelligence services are to investigate unnamed politicians over what’s described as an illegal attempt to seize power.
President Yanukovych has declared Thursday a day of national mourning.