develop nuclear arms.His comments come days after the US said it was modifying its plans for defences against Iranian missiles and shelving a long-range missile shield.
Western powers believe Iran is developing nuclear weapons under the guise of a civilian programme.
Six world powers are to hold talks with Iran on 1 October that are expected to cover global nuclear disarmament.
Ayatollah Khamenei's comments were seen as the first official response to the US decision to scrap a European missile initiative put forward by the former Bush administration to counter any long-range Iranian missile threat.
US President Barack Obama said the US would instead develop sea and land-based interceptors against Iran's short and medium-range missile threat. read more
