World leaders arrive in Istanbul for a summit on the ongoing violence in Syria.<br/> <br />They are hoping to pressure the country's president, Bashar al-Assad, to end a crackdown on opposition groups that has left thousands dead.<br/> <br />Among those calling for an end to violence - British Foreign Secretary William Hague<br/> <br />(SOUNDBITE) (English) BRITISH FOREIGN SECRETARY, WILLIAM HAGUE, SAYING:<br/> <br />"The killing continues, it continues to be a completely unacceptable situation."<br/> <br />Western and Arab powers have been criticized for not doing enough to end the violence in Syria, which has entered its second year.<br/> <br />But German foreign minister Guido Westerwelle says momentum is building for a lasting solution.<br/> <br />(SOUNDBITE) (English) GERMAN FOREIGN MINISTER, GUIDO WESTERWELLE, SAYING:<br/> <br />"It's a crucial time. We think the atrocities and the repression of the regime of Assad is no way acceptable so we will increase our measures."<br/> <br />Meanwhile, a couple of dozen supporters of al-Assad gathered outside the summit hall.<br/> <br />They demanded an end to what they called heavy-handed foreign intervention in Syria.<br/> <br />Andrew Raven, Reuters
