Iranian President Mahmoud Ahmadinejad on Sunday declared Iran had mastered nuclear technology and would never yield in the face of international pressure over its atomic drive. Ahmadinejad's comments in an interview with Iranian television were broadcast hours after French Foreign Minister Bernard Kouchner warned the world should brace for war over Iran, although he did not react to those remarks. "Of course we will not step back," said Ahmadinejad in the interview with Iran's Farsi language international channel Jam-e Jam in response to a call-in question by a viewer.