Iran reserves the right to self-defence and to take protective measures against US actions in the Persian Gulf and the Strait of Hormuz, a senior Iranian diplomat said.

In a letter to the UN secretary-general and the Security Council president, Iran’s ambassador to the UN, Amir-Saeid Iravani, cited recent US military attacks on Iranian oil tankers near the port of Jask and other incidents targeting Iran’s coastal areas.

“These acts, which the US president has openly acknowledged, violate the April 8, 2026, ceasefire and breach Article 2(4) of the UN Charter,” Iravani wrote, referring to a ceasefire announced by President Donald Trump after 40 days of hostilities against Iran.

He criticised the continuation of a US blockade on Iranian vessels as illegal under international law.

Iravani warned that ongoing US aggression could have “catastrophic” consequences, extending beyond the region and threatening global peace and security, for which Washington would bear “full responsibility.”

He accused US forces of seizing Iranian commercial vessels and taking hostages, actions he called “piracy” and incompatible with the responsibilities of a permanent Security Council member.

“The US preference for coercion over diplomacy undermines maritime security and violates fundamental principles of international law,” the envoy added.

Iran urged the UN to demand that the United States adhere to its international obligations and refrain from further provocative measures.