Iran's supreme leader Ayatollah Ali Khamenei vowed on Wednesday that his country would resist global sanctions imposed over its disputed nuclear program, saying that Iran might respond to international pressure by cutting back gas exports."The enemy is using the lever of sanctions to the hilt and their goal is to stop our people's progress," Khamenei said in a public speech in Tehran carried by the official IRNA news agency. "I believe that if we allow them to dictate to us on the nuclear issue, they will still keep the sanctions in place because what they are against is the very foundation of our revolution."Iran is in talks with the United States, Russia, China, Britain, France and Germany to end a decade-old standoff over its nuclear program which the West fears could be used to develop a nuclear bomb. Iran denies having any nuclear weapons ambitions and is seeking an end to international sanctions.