US air strikes on several points along Iran's southern coast are a clear violation of the war-ending memorandum and the UN Charter, Iran's foreign ministry said on June 27.

The strikes mark a sharp escalation barely a week into the 60-day process meant to end the war, with Tehran casting the US action as a breach of an accord signed only days earlier and warning that responsibility for the consequences rests with Washington. The US military said the strikes were a response to an Iranian drone attack on a cargo ship in the Strait of Hormuz, an account Iran disputes.

In a released document, it said the foreign ministry strongly condemned what it described as air strikes by US forces on the evening of June 26, saying they targeted Iranian coastal monitoring facilities and amounted to a clear violation of Article 2(4) of the UN Charter and of the first clause of the war-ending memorandum dated June 18.

It said the Israeli military had at the same time, in coordination with the United States, attacked Lebanon, which it called a clear violation of the memorandum's first clause.

The ministry said Iran would defend its sovereignty, security and national interests with all its power under Article 51 of the UN Charter, and that the armed forces had carried out defensive strikes against targets linked to US forces on that basis.

"Responsibility for the consequences of this situation lies with the aggressor and treaty-breaking US regime and with parties that in any way collaborate in carrying out America's aggressive actions against Iran," it said.

The ministry stressed the need for all countries on the southern shore of the Persian Gulf to adhere to the principle of good neighbourliness and to prevent aggressor parties from using their territory and facilities to commit aggressive acts against Iran.

It also urged the UN secretary-general, the Security Council and other international bodies not to remain indifferent to what it called a flagrant US violation of the UN Charter and international law, and to act on their legal and moral responsibilities for regional and international peace and security.

Iranian state media reported that CENTCOM had released video of US forces attacking Iran after the agreement was signed.

The reports of strikes come after US reconnaissance aircraft were seen flying close to Iranian airspace earlier on June 26, according to an IntelliNews previous report. 

Iran's foreign ministry earlier condemned a joint US-GCC statement as interventionist and provocative, after Gulf foreign ministers and US Secretary of State Marco Rubio set out a hardened common position on Iran's missiles, drones and the Strait of Hormuz at a meeting in Manama, Iran's foreign ministry said on June 26.