(CNN) -- In a blistering speech before the United Nations General Assembly, Iranian President Mahmoud Ahmadinejad blamed "a few bullying powers" for creating the world's problems and said the "American empire in the world is reaching the end of its road."

At the United Nations, Mahmoud Ahmadinejad said countries are turning their backs on "bullying powers."

And while he insisted Iran's nuclear activities are peaceful, Ahmadinejad blamed the same powers for seeking to hinder it "by exerting political and economic pressures on Iran, and threatening and pressuring" the International Atomic Energy Agency.

Those powers, meanwhile, are building or maintaining nuclear stockpiles themselves, unchecked by anyone, he said.