The United Nations Refugee Agency (UNHCR) yesterday expressed «extreme concern» following a string of violent attacks involving immigrants in the district of Aghios Panteleimonas, near central Athens. «The attacks and brawls have created a tense and explosive atmosphere which is unsettling local residents,» the UNHCR said. The agency called on authorities to avert similar attacks and «promote initiatives to tackle social exclusion.» The UNHCR’s appeal follows a recent wave of violence that started with a vicious attack on an Afghan aid worker by 20 assailants last Saturday. On Thursday, three Afghan men were charged with attacking an Albanian minor and two Greek nationals who came to the latter’s aid. Later that day, unidentified arsonists torched a cafe owned by an Afghan and two Bangladeshis stabbed the owner of a local convenience store before fleeing with his takings.