Ahmadinejad, in his first provincial trip after the June 12 presidential vote, said Iran's enemies had tried to interfere and foment aggression in the country, referring to mass opposition protests against the official election result.
The hardline president, who often rails against the West, said the Islamic Republic wanted "logic and negotiations" but that Western powers had insulted the Iranian nation and should apologize.
Iranian leaders often refer to the United States and its allies as the "global arrogance."
"As soon as the new government is established, with power and authority, ten times more than before, it will enter the global scene and will bring down the global arrogance," he told a big crowd in the northeastern city of Mashhad.
"They should wait as a new wave of revolutionary thinking … from the Iranian nation is on the way and we will not allow the arrogant (powers) to even have one night of good sleep," Ahmadinejad said, according to state broadcaster IRIB.
Opposition leader Mirhossein Mousavi, Ahmadinejad's main challenger in the election, says it was rigged in the incumbent's favor. The authorities reject charges of vote fraud.
Iran has accused Britain and the United States, which have criticised a crackdown on opposition protests, of interfering in its internal affairs. London and Washington reject the charge.
"In this recent election the enemy tried to bring the battlefront to the interior of this country," Ahmadinejad said.
"But I have told the enemies … that this nation … will strike you in the face so hard you will lose your way home," he said in comments translated by English-language Press TV.
He also voiced continued defiance in a row over Iran's disputed nuclear ambitions, saying major powers "will not be able to take away the smallest amount of Iran's rights."
Iran says its nuclear program is for peaceful power purposes. Western countries suspect it is aimed at making bombs.
(Reporting by Zahra Hosseinian; writing by Fredrik Dahl; editing by Philippa Fletcher)
