Baqayee Hamaneh made the remarks in the 44th regular session of the Human Rights Council on Thursday.
"The assassination of Lieutenant General Soleimani is an illegal act and a great crime that has endangered world peace and security," he said.
"The US action not only is a violation of international law and the UN Charter, but it is also a violation of human rights law,"
He reiterated that the UN rapporteur's report on the assassination of General Soleimani cannot be challenged.
"The assassination of Lt. Gen. Soleimani is an immoral and dangerous act," said Baqaei Hamaneh.
He called the operation to assassinate the commander of the IRGC's Quds Force "state terrorism", noting that the United States should be held accountable for its actions.
Earlier in a UN session, UN Special Rapporteur Agnes Callamard called the assassination of General Soleimani by the US a clear violation of international law.
The United States has failed to provide sufficient evidence of an ongoing or imminent attack against its interests to justify the strike on General Soleimani’s convoy as it left Baghdad airport, said Callamard.
The US drone strike in Iraq that assassinated General Soleimani and nine other people represented a violation of international law, Callamard said on Monday.
The attack violated the UN Charter, Callamard wrote in a report calling for accountability for targeted killings by armed drones and for greater regulation of the weapons.
“The world is at a critical time and a possible tipping point when it comes to the use of drones. ... The Security Council is missing in action; the international community, willingly or not, stands largely silent,” Callamard said.
"But absent an actual imminent threat to life, the course of action taken by the US was unlawful,” Callamard wrote in the report.
Lieutenant General Soleimani was assassinated in a US drone strike on Baghdad International Airport in Iraq on January 3.
The airstrike also martyred Deputy Commander of Iraq's Popular Mobilization Forces (PMF) Abu Mahdi al-Muhandis. The two were martyred in an American airstrike that targeted their vehicle on the road to the airport.
Five Iranian and five Iraqi military men were martyred by the missiles fired by the US drone at Baghdad International Airport.
Iran announced in late June that it had issued arrest warrants for 36 officials of the US and other countries who have been involved in the assassination of the martyred General Soleimani.
"36 individuals who have been involved or ordered the assassination of Hajj Qassem, including the political and military officials of the US and other governments, have been identified and arrest warrants have been issued for them by the judiciary officials and red alerts have also been issued for them via the Interpol," Prosecutor-General of Tehran Ali Alqasi Mehr said.
He said that the prosecuted individuals are accused of murder and terrorist action, adding that US President Donald Trump stands at the top of the list and will be prosecuted as soon as he stands down presidency after his term ends.