The nearly month-long US-Israeli war on Iran has sparked large-scale Iranian retaliation in the form of drone and missile strikes on energy and civilian infrastructure in Gulf countries, killing civilians and driving up oil prices.
"We are seeing an existential threat to international and regional security. This aggressive approach is undermining international law and sovereignty," Kuwait's ambassador Naser Abdullah HM Alhayen told the Geneva-based council.
Other Gulf states said Iran's actions were designed to spread terror, with the UAE ambassador Jamal Jama al Musharakh denouncing Iran's "attempt to destabilise the international order through reckless adventures of expansionism".
Countries at the 47-member council will vote on a motion condemning Iran's "unprovoked and deliberate" strikes, seeking reparations from Iran and asking the UN rights chief to monitor the situation, a document showed.
Iran defended its actions, saying more than 1500 civilians had been killed in the US-Israeli strikes so far.
"We fight on behalf of all of you against an enemy that, if not restrained today, will be beyond containment tomorrow," said Iran's ambassador to the UN in Geneva, Ali Bahreini, referring to Israel.
Iran, backed by China, will hold its own emergency session on a fatal strike on a primary school on Friday.
The United Nations' top rights official, Volker Turk, urged states to end the Iran conflict, describing the situation as extremely dangerous and unpredictable.
"Attacks on civilians and civilian infrastructure must end. If they are deliberate, such attacks may constitute war crimes," he told the council.
While Gulf states received strong backing in the council on Wednesday, the International Service for Human Rights, an independent NGO, warned against "selective outrage", calling instead for a focus on violations by all perpetrators.
Oman, which had served as a mediator between the United States and Iran before the conflict, was one of the few countries to acknowledge that US-Israeli strikes had preceded Iran's retaliatory attacks.
"(They were) the spark that ignited the escalation currently affecting the region and the consequences are threatening states and their vital economic interests and their security and stability," ambassador Idris Abdul Rahman Al Khanjari told the council.
