Protests against the Roma community have taken place in the northern Bulgarian city of Gabrovo, sparked by an alleged attack by Roma men on a shopkeeper.

Nine people were arrested and three reported injured Thursday evening during the latest clashes between protesters and police.

Deputy Prime Minister Tomislav Donchev, a former Gabrovo mayor, visited the city to appeal for calm, but was booed by the crowd.

Some Roma parents are keeping their children out of school, fearing for their safety if they leave their neighborhood.

Donchev said ethnic tensions in Gabrovo have existed for years. A decision was made recently to demolish derelict houses, often used illegally by Roma.

Roma, or Gypsies, make up around 5-9% of Bulgaria's population of 7 million and are among the most disadvantaged groups in the country.