President Mahmoud Ahmadinejad dismissed on Friday as a "childish move" international sanctions on Iran, a day after Washington extended one of many sets of sanctions on the country.

"If you (world powers) had not blocked the road, Iran would have not become a nuclear power nation and would have not a presence in space," Ahmadinejad was quoted as saying by the official IRNA news agency in the Gulf port city of Assalouyeh.

"They thought that by childish and harassing moves they can stop a great nation''s scientific path towards perfection," he added inaugurating a gas refinery there.

"You take your decisions and we do our work, since knowingly or unknowingly you have opened our nation''s path to progress, and you too small to block our path," he said.

His comments come a day after US President Barack Obama said he had extended one of the many levels of sanctions against Iran, imposed in 1995 over claims Tehran dealt in terrorism and sought weapons of mass destruction.

The United States and other global powers suspect that Iran is using its civilian nuclear programme as a cover for developing nuclear weapons, something Tehran strongly denies.