Tensions between Iran and the United States reignited after Washington blamed Tehran for the downing of a US military helicopter, prompting retaliation from Iran and likely adding obstacles to ending the war amid weeks of deadlock.

US President Donald Trump in a social media post said the Iranians shot down a highly sophisticated Apache helicopter while it was patrolling the Strait of Hormuz.

"There were two pilots involved, both are safe and uninjured. Nevertheless, the United States must, of necessity, respond to this attack," said Trump.

The US Central Command, or CENTCOM, said in a post on social media platform X that forces began launching "self-defense strikes" against Iran at 5 pm on Tuesday at the commander-in-chief's direction.

"CENTCOM forces struck Iranian air defense, ground control stations, and surveillance radar sites near the Strait of Hormuz with precision munitions from US Air Force and Navy fighter jets. The operation was a proportional response to recent attacks on US forces and international commercial ships transiting regional waters," it said.

It added that the US forces remain vigilant and postured to defend against "unjustified Iranian aggression".

Iranian Foreign Minister Abbas Araghchi said in a post on X that despite its "defeats on the battlefield", the "US opted to test our determination" as he warned that Iran's armed forces "will leave no attack or threat unanswered".

"Leave our region if you want to be safe. History of the Persian Gulf has many chapters on dire fates of intruding outsiders," said Araghchi.

Araghchi also held separate phone calls with his Turkish and Saudi counterparts, reviewing the latest regional developments in the wake of US military strikes against areas in southern Iran.

The calls, in the early hours of Wednesday, covered the rapidly evolving security situation following US aggression against Iranian territory, Iranian media reported.

Araghchi condemned the US military strikes as a violation of Iranian sovereignty and territorial integrity. He underscored Iran's right to self-defense and affirmed the legitimacy of the retaliatory response carried out by Iran's armed forces.

Iran's Foreign Ministry condemned US strikes on southern Iran as a violation of the United Nations Charter.

The Iranian Foreign Ministry also reminded regional countries, particularly those on the southern shores, of the Gulf of their legal and moral responsibility to prevent the US military and Israel from using their territory, facilities or infrastructure to plan, organize, execute or support aggressive operations against Iran.

The Islamic Revolutionary Guard Corps said it struck a US air base in Jordan on Wednesday, hitting four key targets, including F-35 fighter shelters. It also said that it attacked the US Fifth Fleet in Bahrain.

Contact the writers at jan@chinadailyapac.com