Iranian President Mahmoud Ahmadinejad accused the West of abusing the United Nations to try to deny Iran the right to the peaceful nuclear technology which Western states enjoy.
His speech offered no hint of willingness to comply with UN demands that Tehran suspend uranium enrichment, which can be used to produce fuel for power stations or bombs.
"The abuse of the Security Council, as an instrument of threat and coercion, is indeed a source of grave concern," Mr Ahmadinejad told the UN General Assembly.
Iran's atomic activities are "transparent, peaceful and under the watchful eyes of IAEA inspectors," he insisted, referring to the UN nuclear watchdog.
Earlier, US President George W Bush accused Iran's rulers of spending their resources on funding terrorists and pursuing nuclear weapons and demanded Iran abandon what he called "its nuclear weapons ambitions."
Mr Ahmadinejad said the United States, Britain and others themselves benefited from nuclear energy and the fuel cycle.
"Some of them have abused nuclear technology for non-peaceful ends including the production of nuclear bombs, and some even have a bleak record of using them against humanity," the president said.
He delivered another tirade against Israel, declaring, "the pretexts for the creating of the regime occupying al-Qods al-Sharif (Jerusalem) are so weak that its proponents want to silence any voice trying to merely speak about them."
The Iranian leader sparked international protests last year when he called for Israel to be wiped off the map.
He contrasted what he called "blanket and unwarranted support" for the Jewish state with silence when democratically elected Palestinian ministers and members of parliament were "illegally abducted and incarcerated in full view of the international community".