Protesters jeered at German Chancellor Angela Merkel on Monday as she attended celebrations in the eastern city of Dresden to mark 26 years since Germany’s reunification. Holding placards reading “Merkel must go”, right-wing protesters also shouted the slogan as Merkel, who has faced criticism for her open-door refugee policy, and President Joachim Gauck arrived for the celebrations and greeted spectators. German media estimated the number of protesters at “several hundred”. Dresden was the cradle of the anti-Islam PEGIDA grassroots movement, whose weekly rallies attracted around 20,000 supporters at their height at the start of 2015. Last year’s arrival of around a million migrants, mainly Muslims fleeing conflict and poverty in the Middle East, Africa and Asia, has increased social tensions. In a short statement, Merkel, who grew up in East Germany, called for “mutual respect” in the political debate and said she wished that all sides could work together to tackle the new problems regardless of their different political views. Security has been tightened for the celebrations, known as German Unity Day, with some 2,600 police officers on duty after two improvised bombs exploded in Dresden last week, one at a mosque and one at an international conference center. On Saturday, three police cars were set alight by unknown perpetrators in the city.