At least 18 die in Ukraine clashes

But after the outburst of violence against riot police, Yanukovych's government may have felt it had no choice but to try to restore order.

While Kiev and western Ukraine have risen up against Yanukovych, he remains popular in the Russian-speaking eastern and southern regions, where economic and cultural ties with Russia are strong.

As darkness fell, law enforcement agencies vowed to bring order to the streets and they shut down subway stations in the center of the capital.

In Independence Square, Orthodox priests prayed for peace.

‘‘We see that this regime again has begun shooting people; they want to sink Ukraine in blood. We will not give in to a single provocation,'' opposition leader Arseniy Yatsenyuk told the protesters. ‘‘We will not take one step back from this square. We have nowhere to retreat to. Ukraine is behind us, Ukraine's future is behind us.''

Tuesday's clashes were the first to lead to deaths since Jan. 22, when two protesters were hit with live ammunition and a third died after a fall.

As angry protesters outside parliament hurled stones at police and set trucks blocking their way on fire, riot police retaliated with stun grenades and fired what appeared to be small metal balls, as smoke from burning tires and vehicles billowed over Kiev.

Early Wednesday morning, government agencies said 18 people died in the violence, including seven policemen who died from gunshot wounds.