Ukraine police on Wednesday used tear gas and several people were injured at a chaotic protest against a new language law as the president summoned the leaders of parliament to limit a growing crisis.
The opposition has reacted furiously to the rushed passing by the Ukrainian parliament the Verkhovna Rada late on Tuesday of the law elevating the status of Russian, which was not on the parliament's agenda for that day.
Around 1,000 people, including boxing star and opposition figure Vitali Klitschko, staged an angry protest in the centre of Kiev and were rapidly involved in clashes with a large force of anti-riot police, an AFP correspondent said.
Several people were left covered in blood and broken glass littered the street. Klitschko said a bottle was thrown during the brawl, injuring his hand.
The police used tear gas in an apparent bid to bring the situation under control.
Ukrainian President Viktor Yanukovych also summoned parliament's speakers and faction chiefs for an urgent meeting to defuse the growing standoff after Verkhovna Rada speaker Volodymyr Lytvyn offered to resign.
Lytvyn has expressed outrage that he was not warned by other parliament leaders that they planned to vote on the language law in a second and final reading. He was not even present in the chamber when the vote took place.
"The president has invited the leadership of the Verkhovna Rada to discuss the situation in parliament," Yanukovych's office said in a statement.
The meeting meant that the presidency also made the unprecedented move of postponing a major news conference by Yanukovych that was scheduled at the same time and expected to be attended by hundreds of journalists.
The protest took place outside the Kiev conference centre where Yanukovych was scheduled to talk to the press. The demonstration broke up by midday but no new time for the press conference was announced.
Lytvyn -- who heads his own bloc but has often sided with Yanukovych -- meanwhile complained bitterly of his treatment by parliament.
"I was cheated, Ukraine was cheated, the people were cheated," he said of Tuesday's vote, quoted by the Interfax-Ukraine news agency.
Turning on one of his deputy speakers, Communist lawmaker Adam Martynyuk who presided over Tuesday's vote, he added: "This is my former comrade, with whom I shared bread and salt, and who gave me up. Completely."
His offer to resign still has to be approved by the deputies to come into force. Lytvyn's signature is needed to confirm that the bill has been passed.
The chaos appears to be a return to business as usual for Ukraine -- which has a well-earned reputation for political instability -- after its friendly and efficient hosting of the Euro-2012 football impressed foreign fans.
The language law was pushed through by the majority from Yanukovych's Regions Party but it is unclear if he supported the strong-arm tactics that were used to adopt it.
The bill -- which still needs to be signed by Yanukovych -- says Ukrainian is the official language but states that minority languages can be used by officials and bodies in regions where the population uses these languages.
This gives a boost to Russian, historically the language of eastern Ukraine and the Crimean peninsula, and the opposition fears that the law will undermine the use of the Ukrainian language.
"This is not a language issue, this is a splitting of the country," Klitschko, who heads Kiev-based political party Ukrainian Democratic Alliance for Reform told reporters at the protest.
The crowd chanted the traditionally nationalist slogans like "Glory to Ukraine, glory to heroes," and "Glory to the nation, death to the enemies," and held several signs including one that read "For the language, for Motherland."