Bulgarian Interior Minister Rumyana Bachvarova said on Monday there had been "provocateurs" at the protest rallies in the town of Radnevo, where tensions rose last week between ethnic Bulgarians and Roma residents.

A scuffle over the right of way on a local road was followed last Monday by demonstrations demanding justice for the victims, ethnic Bulgarians, beaten and left with serious injuries by four Roma people.

The four men were charged with attempted murder and taken into custody. Residents of Radnevo, however, say wrongdoing by Roma is often left unpunished, particularly acts committed by one Roma family.

On Monday Bachvarova told private NOVA TV station police were currently looking into "who sent them," referring to the alleged "provocateurs".

She said she disbelieved the police could turn a blind eye on incidents related to Roma people, adding officers were carefully monitoring any criminal case that occurred in areas of "mixed" ethnic composition.