The Ukrainian government blasted ultra-nationalists for the bloodshed, as the European Union, Germany and Russia voiced their concern.
It was the worst unrest in the capital since a popular uprising ousted Moscow-backed president Viktor Yanukovych early last year, unleashing a separatist insurgency in Ukraine's industrial east.
Prime Minister Arseniy Yatsenyuk pointed the finger at ultra-nationalists for the violence, which left 125 injured, six seriously, according to the interior ministry.
President Petro Poroshenko branded the violence a "stab in the back" and said the perpetrators deserved "severe" punishment.
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The EU, the Kremlin and Germany all expressed concern.
"Today's events are very worrying," said EU foreign affairs head Federica Mogherini while Russian President Vladimir Putin's spokesman condemned the "displays of violence" in Kiev.
"Street violence is unacceptable under any circumstance, but violence against the decisions of an elected parliament is even more so," the German foreign ministry said.