Iranian President Hassan Rouhani hit out at the US over its decision to impose economic sanctions, in his address at the United Nations General Assembly.
Speaking in a recorded video message, the Iranian leader complained about US actions around the world in the past and the present.
He also thanked permanent UN Security Council members Russia and China for their support at the end of August in a vote on the reintroduction of sanctions.
“Iran, instead of enjoying global partnership and co-operation, is grappling with the harshest sanctions in history imposed in blatant and gross violation of the Charter of the United Nations,” Mr Rouhani said.
“I should express our appreciation to the presidents of the Security Council … as well as 13 of its members, especially Russia and China, who twice said a decisive and resounding 'no' to the unlawful use attempt to exploit the council and its Resolution 2231.”
The UN Security Council in August blocked a bid by Washington to impose sanctions on Iran.
The administration of US President Donald Trump has accused Iran of failing to comply with the terms and live up to the spirit of the nuclear deal it signed in 2015.
As part of the Joint Comprehensive Plan of Action, Iran pledged to give up its nuclear ambitions in exchange for sanctions relief.
Washington said it had the legal right to trigger the deal’s snapback procedure under Resolution 2231 to re-impose sanctions despite withdrawing from the agreement in 2018.
Despite the vote by the Security Council in August and statements by UN Secretary General Antonio Guterres, Mr Trump on Monday signed an executive order to enforce UN sanctions on Tehran as his administration announced penalties against people and entities linked to Tehran's weapons programmes.
Tensions between Tehran and Washington have been at the heart of regional frictions that have frequently threatened to boil over.
In January, the two nations seemed on the verge of an all-out conflict after the killing of Iranian general Qassem Suleimani in a US strike in Baghdad.
Mr Rouhani hit out at the US over the killing in his UN General Assembly speech, repeating praise regularly broadcast from Iranian state media outlets that referred to Suleimani as a martyr and a hero.
He also defended Iran’s actions in the wider region. The US cited Iran’s support of regional proxies as part of its motivation for withdrawing from the JCPOA, but Mr Rouhani defended Tehran’s strategy, particularly in Iraq, Syria and Lebanon.