BRUSSELS (Reuters) - The European Union is prepared to ramp up sanctions against North Korea after it conducted its sixth and most powerful nuclear test on Sunday, European Council President Donald Tusk said.  The EU stands ready to sharpen its policy of sanctions and invites North Korea to restart dialogue on its programers without condition,  Tusk said in a statement.  We call on the UN Security Council to adopt further UN sanctions and show stronger resolve to achieve a peaceful decentralization of the Korean peninsula. The stakes are getting too high.  
EU's Tusk says ready to ramp up sanctions against North Korea