Strait of Hormuz [File photo courtesy of Reuters/Yonhap News]

Nine days after officially signing a Memorandum of Understanding (MOU) to end hostilities, the United States and Iran clashed again on the 26th (local time).

As both sides exchanged fire while follow-up negotiations were underway following the signing of the MOU, the ceasefire agreement now faces a major turning point.

In a statement posted on X (formerly Twitter) that day, U.S. Central Command (CENTCOM), which oversees U.S. forces in the Middle East, stated, "U.S. Central Command forces conducted airstrikes against Iran on the 26th as a strong response to the attack yesterday (25th) on a merchant vessel transiting the Strait of Hormuz."

CENTCOM explained that U.S. military aircraft struck Iranian missile and drone storage facilities, as well as coastal radar stations, during the operation.

The Iranian attack on the 25th, which the U.S. cited as the justification for this strike, refers to a drone attack on the 'Ever Lovely,' a Singapore-flagged container ship attempting to transit the Strait of Hormuz.

CENTCOM criticized the move, stating, "The unjustified attack by Iranian forces on a merchant vessel is a clear violation of the ceasefire," and added, "Furthermore, Iran's dangerous actions have undermined the freedom of navigation at a time when commercial traffic through this vital international trade route is steadily increasing."

The statement continued, "CENTCOM forces continue to provide safe transit coordination and support for merchant vessels passing through the Strait of Hormuz," and emphasized, "The U.S. military remains stationed in the region, maintaining vigilance to ensure that all aspects of the agreement with Iran are upheld, implemented, and fully effective."

U.S. Vice President JD Vance wrote on X, "Iran signed the ceasefire agreement. We have been upholding that agreement," adding, "If they (Iran) have disagreements on how the MOU is implemented, they can pick up the phone. But we will meet violence with violence."

Prior to this, U.S. President Donald Trump also criticized Iran’s attack on the merchant vessel in the Strait of Hormuz, calling it a "clearly foolish violation of the ceasefire agreement" and signaled the possibility of a response.

Iran did not remain idle following the U.S. airstrikes.

The Islamic Revolutionary Guard Corps (IRGC) labeled the U.S. attack that day a "violation of the ceasefire" and announced that it had struck U.S. military bases in the Middle East.

In a statement released on the 27th (local time), the IRGC announced, "Following the Zionist regime's (Israel's) violation of the ceasefire in southern Lebanon, the American regime has once again broken its promise, as it always does, by violating the (ceasefire) agreement," and added, "In response to this aggression, the IRGC Navy has struck several bases of the U.S. terrorist forces in the region."

The IRGC further confirmed the U.S. attack against them, stating, "The United States used various pretexts to attack the Iranian coast, citing the transit of a 'violating ship' that was passing through unauthorized routes in the Strait of Hormuz."

Earlier, Iranian state television reported on the 26th that a communications tower in Sirik, an Iranian port city in the south near the Strait of Hormuz, was hit by two projectiles. State media also reported that two projectiles landed on Qeshm Island in the Strait of Hormuz. The source of the projectiles was not mentioned.

Ebrahim Azizi, Chairman of the Iranian Parliament's National Security and Foreign Policy Committee, also stated on X on the 27th, "The U.S. has once again attacked Iran during negotiations," and claimed, "The failing U.S. President has not upheld the principles of negotiation or the ceasefire."

Chairman Azizi further argued that according to Article 5 of the Islamabad Agreement (the peace MOU), the control procedures and authority for transit in the Strait of Hormuz rest with Iran. He warned that the U.S. is attempting to violate this in various ways and that any future repetitions would be met with a more extensive response.

The ceasefire MOU, agreed upon by the U.S. and Iran on the 14th and officially signed and enacted on the 17th, stipulates the immediate and permanent cessation of military operations on all fronts.

Since then, both sides have been engaged in follow-up negotiations regarding Iran's nuclear program and the lifting of sanctions against Iran. However, the agreement has faced a trial almost as soon as the ink dried, following incidents such as the temporary postponement of talks as Israel continued its attacks against Hezbollah, a pro-Iranian militant group in Lebanon.

The U.S. attack on Iran is primarily being read as a warning message from Washington to Tehran. The Trump administration's primary goal in pursuing peace with Iran through the MOU was the normalization of traffic in the Strait of Hormuz; with Iran's attack on a merchant vessel once again disrupting transit, it appears the U.S. chose a military strike to deliver a firm message.

Conversely, Iran’s counter-strike on U.S. bases is seen as a signal that it did not agree to the MOU from a position of weakness, and that it will not easily yield in future negotiations with the U.S. over issues like denuclearization and the lifting of sanctions.

With the U.S. midterm elections approaching in November, the Trump administration faces significant political pressure regarding the resumption of war, and Iran views the MOU as a favorable achievement. Therefore, both sides may remain cautious about completely abandoning the peace agreement through further escalation.

However, there is growing concern that if both sides—lacking mutual trust and sensitive to domestic public opinion—continue to engage in "tit-for-tat" military responses, they could face an uncontrollable, unexpected situation, such as significant military casualties, which could cause the fragile MOU framework to collapse.