Turkey defied the other 27 members of NATO on Saturday by blocking the appointment of their choice as the military alliance's next leader, undermining a show of unity at a 60th anniversary summit. Violent clashes between police and anti-NATO protesters also soured the atmosphere at a summit where US President Barack Obama was trying to drum up support for the Afghan war and leaders hoped to forge a new strategic vision for the alliance. The protesters set ablaze a former frontier post on the Franco-German border and police fired teargas and shock grenades to try to contain the violence. At least 50 people were injured. Turkey refused to accept Europe's candidate for the post of NATO secretary-general, Danish Prime Minister Anders Fogh Rasmussen, citing his handling of a row in 2006 over cartoons of the Prophet Muhammad (pbuh) that offended Muslims. Rasmussen had defended their publication at the time on the grounds of free speech and refused to apologize to Muslim countries. “Why should Turkey agree on a candidate today? Yesterday the (Turkish) prime minister spoke about it and we are sticking with that idea,” a senior Turkish government official said Turkish Prime Minister Tayyip Erdogan had urged NATO to look for alternatives to Rasmussen. A long telephone call between Italian Prime Minister Silvio Berlusconi and Erdogan on Saturday morning failed to break the deadlock. NATO members came to the summit in the French city of Strasbourg and German towns of Kehl and Baden-Baden hoping to forge a new strategic vision for an alliance that was created soon after World War Two to defend Europe's borders. The group has expanded to 28 nations but is struggling in Afghanistan, seven years after US-backed forces toppled the Taleban. The summit will bring France back into NATO's military structures and welcome new members Albania and Croatia.