Iran's president says if new international sanctions are passed against his country, relations with the United States will never improve.<br /><br />Mahmoud Ahmadinejad was speaking a day after western diplomats walked out during his speech at a United Nations nuclear non-proliferation conference in New York.<br /><br />He spoke to Al Jazeera's Shihab Rattansi about Iran-US ties, as well as the possibility of reaching an agreement on Iran's nuclear aspirations. (May 5, 2010)