Ukrainian police say 141 people remain hospitalized after a nationalist protest in Kiev turned violent, with 10 of the injured in serious condition.

This is up from the 122, mostly police officers and National Guard troops, cited Monday by the interior minister. One officer died from his wounds.

The nationalist protesters clashed with police outside Ukraine's parliament on Monday as lawmakers voted to give greater powers to Russia-backed separatists in eastern Ukraine.

About 30 people were detained, and police said Tuesday that 18 remained in custody.

The decentralization of power was a condition demanded by Russia for a truce signed in February aimed at ending the fighting between government troops and Russia-backed separatists that has left more than 6,800 dead since April 2014.