Iran's foreign ministry defended the country's naval blockade of the Strait of Hormuz and its strikes on tankers as legitimate self-defence against US aggression, in a statement issued on August 1.

The statement sets out Tehran's formal legal case for actions that have choked one of the world's most important oil chokepoints, framing continued US military operations rather than Iran's own conduct as the cause of the disruption.

It came the same day the IRGC said it had struck two more tankers attempting to transit the strait, and hours after Iran's waterway authority said it would issue no transit permits until US military operations ceased.

The ministry said the US had continued to breach the ceasefire understanding that ended the war on June 18 through a maritime siege of Iran's ports and shipping, alongside attacks on various regions, economic pressure and what it called unlawful threats.

It said the continued naval siege met the United Nations definition of aggression under General Assembly resolution 3314 of December 14, 1974, and that Iran reserved the right to use all means for legitimate self-defence.

The ministry said a new round of what it described as US military aggression had begun on the evening of July 8, coinciding with funeral ceremonies for the supreme leader, using as a pretext claims of incidents involving three ships crossing an unsafe and unauthorised route through the strait.

It said countries whose ships were involved had known that management of the strait rested with Iran and that the southern route was unauthorised, yet had attempted to send the three vessels through it.

It said such actions violated a fifth clause of the ceasefire understanding, coming only days after the accord was signed, alongside provocative statements by the Gulf Cooperation Council and intervention by US Secretary of State Marco Rubio dated July 26.

The ministry said that between July 27 and July 8, US forces had repeatedly misused commercial vessels to move military personnel, equipment and materiel, and that vessels using the southern route with transponders switched off were seeking to evade Iranian monitoring. It said that on July 8 a CENTCOM warship had crossed the southern route under cover of a large gas tanker.

The US military has rejected Iran's claim to control the strait, saying its forces remain in the region to ensure freedom of navigation, and has directed hundreds of strikes against Iranian targets in the south. The confrontation has left tankers hit and crews killed in recent weeks, and shipping largely suspended through the waterway, which normally carries about a quarter of the world's seaborne oil.

The ministry said Iran held no hostility towards regional states and sought friendly relations based on mutual respect and good neighbourliness with all countries bordering the southern Persian Gulf.