The EU presidency on Saturday called for the establishment of an international tribunal for war crimes after new mass graves were found in Ukraine. “In the 21st century, such attacks against the civilian population are unthinkable and abhorrent,” said Jan Lipavsky, foreign minister of the Czech Republic which holds the European Union’s rotating presidency. “We must not overlook it. We stand for the punishment of all war criminals,” he added in a message on Twitter. “I call for the speedy establishment of a special international tribunal that will prosecute the crime of aggression”. Russia left…