A raucous welcome for President Barack Obama on the last stop of his South Korea trip.<br/> <br />Obama was greeted by U.S. troops at the Yongsan garrison and a sea of mobile phones.<br/> <br />The U.S. president's week long Asia tour comes as North Korea sends out new signals it's preparing for a fourth nuclear test.<br/> <br />But Obama warned that the U.S. would respond to any "provocations" by Pyongyang.<br/> <br />(SOUNDBITE) (English) BARACK OBAMA, UNITED STATES PRESIDENT, SAYING:<br/> <br />"The 38th parallel now exists as much as a contrast between worlds as it does a border between nations. Between a society that's open and one that is closed. Between a democracy that is growing and a pariah state who would rather starve it's people than feed their hopes and dreams. That's not the result of a war that's the result of the path that North Korea has taken, a path of confrontation and provocation and pursuing the world's most dangerous weapons. And I want to be clear, the commitment that the United States
