Ukrainian President Viktor Yanukovych on Monday slammed the protests against his rule as "extremism" and "radicalism" and appared to link them to Nazism, taking a hard line against the opposition after returning from sick leave.

"We have to say no to the extremism, radicalism and incitement to hatred in society behind which there is a struggle for power," he was quoted as saying in a statement issued by the presidency.

Yanukovych, who has been off for four days with a respiratory infection, was meeting with members of a roundtable entitled "The Democratic Process and the Threat of Radicalism in Ukraine".

"The vandalism that we have seen in the occupation of state institutions and the calls that we hear are reminiscent of our old history. We would not want it to be repeated," he said.

Yanukovych thanked participants at the meeting for "uniting people in a community of wholesome people without Nazism, racism and the xenophobia that remind us of the terrible lessons of history."