A Ukrainian lawmaker has punched his colleague in the face, the latest brawl in the nation's raucous parliament.

Opposition Bloc head Yuri Boiko first listened calmly as Radical Party head Oleh Lyashko was denouncing him as a Kremlin agent in Ukraine during Monday's meeting of parliamentary leaders. Suddenly, he jumped to his feet, grabbed Lyashko by the neck and hit him in the face with his fist.

As Lyashko again took the floor, calling Boiko a "Moscow louse," Boiko hit him again.

Others pulled them apart, and Verkhovna Rada speaker Andriy Parubiy warned Boiko that he could be barred from attending parliament meetings.

Ukrainian police have launched an investigation.