President Viktor Yanukovich has signed a controversial law which will make Russian the official language in parts of Ukraine.
There have already been brawls in parliament over the bill. Language is a deeply sensitive issue in the traditionally bilingual former Soviet republic.
The president’s political opponents denounce the law as an assault on Ukrainian identity. They have staged protests in the capital, Kiev.
Ukrainian remains the state language. However, under the legislation, minority languages can be used in state institutions in areas where they are spoken by more than 10 percent of residents.
In practice, that will mean Russian becoming an official regional language in predominantly Russian-speaking areas of the industrialised south and east.