Riot police fired tear gas and used batons to push back protesters, led by opposition members of Parliament, who had massed in front of a building where President Viktor Yanukovich was due to hold a press briefing.

They urged Yanukovich -who had planned a celebratory statement to crown the successful co-hosting of the Euro 2012 soccer tournament - to veto the bill, which was rammed through Parliament late on Tuesday by the majority Party of Regions.

Yanukovich said on Wednesday Ukraine may have to hold an early parliamentary election if the crisis continues.

Yanukovich met the heads of several Parliament factions to discuss what he called a crisis in the legislature after its speaker Volodymyr Lytvyn offered to resign.

Lytvyn tendered his resignation at the opening of the parliamentary session.

The chamber approved the language bill in a second and final reading on Tuesday minutes after a proposal by one of the pro-Yanukovich deputies, giving opponents little time to cast their vote and prompting scuffles both in Parliament and on the streets.

Many protesters stayed out on the streets of central Kiev overnight.

Mykola Tomenko, a deputy speaker, had also stepped down.

The bill would upgrade the status of Russian in the former Soviet republic, where the official state language is Ukrainian.

If signed into law, the bill would recognize Russian as a "regional" language in predominantly Russian-speaking areas, enabling its use in the public service.

Reuters