"Iran will do whatever it can to divert attention away from its own record in an attempt to evade accountability," she said.
"Iran is the only country represented in this hall that has been found by the [International Atomic Energy Agency] board of governors to be currently in non-compliance with its nuclear safeguard obligations."
"It has defied the UN Security Council and the IAEA and placed the future of the non-proliferation regime in jeopardy, and that is why it is facing increasing isolation and pressure from the international community," she added.
The US is currently negotiating with other Security Council members to impose a fourth round of UN economic sanctions against Iran over its uranium enrichment programme.
Tehran insists its nuclear programme is entirely peaceful.
The Nuclear Non-Proliferation Treaty (NPT) comprises a grand bargain, BBC Diplomatic correspondent Jonathan Marcus says.
Mahmoud Ahmadinejad criticised nuclear powers for failing to disarm
The five major nuclear powers - the US, the former Soviet Union, China, the UK and France - agreed to eventually disarm. Other signatories agreed never to develop nuclear weapons in return for receiving full access to civilian nuclear technology.
But, our correspondent says, the bargain is looking increasingly threadbare, with critics arguing that the original nuclear weapons states have not taken their disarmament responsibilities seriously.
In his speech, Mr Ahmadinejad criticised nuclear powers for failing to disarm, saying their "production, stockpiling and qualitative improvement of nuclear armaments... now serves as a justification for the others to develop their own".
"The nuclear bomb is a fire against humanity, rather than a weapon of defence. The possession of nuclear bombs is not a source of pride. Its possession is disgusting and shameful," he said.
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