Iranian media reported on Thursday evening that explosions were heard in the Strait of Hormuz.
Channels identified with the Iranian Revolutionary Guard Corps (IRGC) later claimed that the IRGC launched missiles at four US merchant ships which tried to pass through the Strait without Iranian permission.
The incident comes a day after the US military carried out strikes in Iran targeting a military site that officials believed posed a threat to US forces and commercial maritime traffic in the Strait of Hormuz.
A US official, who spoke on condition of anonymity, told Reuters that the US military also intercepted and shot down multiple Iranian drones that posed a similar threat.
The strikes marked the second time this week that American military forces executed a series of preemptive, defensive airstrikes in Iran, after similar strikes on Monday.
On Tuesday, Iran's Foreign Ministry accused the United States of repeatedly violating the ceasefire agreement by striking targets in Iran.
According to the regime's diplomatic apparatus, the United States has persisted in executing what it characterized as “unlawful and unjust actions" since the implementation of the truce.
The Ministry specifically alleged that American forces have committed “numerous maritime robberies" against Iranian commercial vessels, while further asserting that Washington flagrantly violated the ceasefire within Iran’s strategic Hormozgan region over the preceding 28 hours.