The US military said Tuesday it was ready to resume "major combat operations" if Iran retaliates against its operation in the Strait of Hormuz, following clashes at sea and attacks against the United Arab Emirates attributed to Tehran.

While Iran has "categorically" denied carrying out strikes against its neighbor on Monday and Tuesday, US President Donald Trump earlier refrained from accusing it of violating the ceasefire, in effect since April 8, during a press briefing. "They know what they have to do and (...) what they must not do," he stated.

Since the start of the war launched on February 28 by the United States and Israel against the Islamic Republic, which has caused thousands of deaths, especially in Iran and Lebanon, Tehran has controlled the Strait of Hormuz, which is strategic for the global trade of hydrocarbons.

Trying to find a way out of this situation, which is causing oil prices to soar, Washington imposed a blockade of Iranian ports on April 13 and launched Operation Project Freedom on Monday to allow hundreds of ships stuck in the Gulf to cross the strait.

Iran retaliated on Monday with missile and drone strikes against US military facilities – which were intercepted, according to the US Central Command (Centcom). It was also accused of firing on the United Arab Emirates, in the first attack against a Gulf state since the ceasefire, a claim denied by a senior Iranian military official on Tuesday evening.

"The armed forces of the Islamic Republic of Iran have not conducted any missile or drone operations against the United Arab Emirates in recent days," said the spokesman for the military command headquarters.

Earlier, the Emirates indicated that they had again activated their air defenses to intercept missiles and drones that they said were fired from Iran.

- "Not much clarity" -

Iran's Revolutionary Guards, its ideological army, have threatened a "firm response" to any ship that does not comply with the passage rules imposed by Tehran.

The United States cannot "allow Iran to block an international shipping lane," Defense Secretary Pete Hegseth had previously insisted.

"If you attack innocent American troops or commercial vessels, you will face overwhelming and devastating American force," he warned. The military "is ready to resume major combat operations against Iran," Chairman of the Joint Chiefs of Staff Dan Caine affirmed at his side.

The speaker of the Iranian Parliament, Mohammad Bagher Ghalibaf, accused the United States and its allies of "endangering" the security of maritime transport.

"There is little clarity on how Project Freedom will ensure a safe evacuation, nor any guarantee from Iran," warned the International Transport Workers' Federation (ITF), calling for the approximately 20,000 sailors currently "held hostage" in the Gulf not to be endangered.

Centcom asserts, despite Iranian denials, that two merchant ships flying the American flag, under military escort, crossed the Strait of Hormuz on Monday.

The operation, marked according to the army by the destruction of six Iranian boats, "is going very well," Donald Trump said.

The Danish shipping giant Maersk also announced the departure on Monday of one of its ships, "accompanied by American military assets", stuck in the Gulf since the beginning of the war.

Here too, Tehran denied any damage to its ships, accusing the United States of killing five civilians by targeting two boats traveling from Oman to the Iranian coast.

- "Escalation" -

The Emirati Ministry of Foreign Affairs denounced on Monday "a dangerous escalation", particularly after a drone attack on the Fujairah oil site.

In this context, the price of Brent crude, the international benchmark, remains at very high levels, around $110, although still below the peak of $126 reached last week.

In the absence of an agreement, "an escalation involving more targeted and sustained attacks, likely to cause deeper and more lasting damage to infrastructure, seems probable," warn Sidharth Kaushal and Dan Marks of the British research center Rusi.

Attempts to revive talks between Iran and the United States have stalled since the first direct meeting in Islamabad on April 11.

Iranian President Massoud Pezeshkian said on Tuesday that his country was "ready for any dialogue (...) but (...) it has never given in and will never give in to force," during a telephone conversation with the Iraqi Prime Minister.

AFP