Iran's new president skirted the nuclear dispute with Europe and the United States on in his first address to the General Assembly.
With a possible showdown looming between his country and the UN Security Council, he warned the world body not to bend to US pressure and scolded the Americans for a dispute over the visa he was given to attend the summit.
Iran, which is under mounting pressure to halt its uranium conversion, says its nuclear technology is for the peaceful production of energy.
The United States and other countries suspect Iran may be seeking to produce nuclear weapons and have warned they may refer it to the UN Security Council for possible sanctions.
President Mahmoud Ahmedinejad said taking punitive measures over intentions rather than actions contradicts the principles of the UN
"The raison d'etre of the United Nations is to promote global peace and tranquillity," he told the General Assembly.
"Therefore, any license for pre-emptive measures which are essentially based on gauging intentions rather than objective facts . . . is a blatant contradiction to the very foundation of the United Nations and the letter and the spirit of its charter," he said.
The United States and European countries warned last week that Tehran is running out of time to freeze uranium processing activities or face referral to the Security Council.
Tehran has dismissed the threat. On Sunday, the Iranian foreign minister said his country wants to continue dialogue on the issue with Europe without preconditions.
Britain, France and Germany have been negotiating with Iran on the nuclear issue.
AP