The United States and Iran inched closer to a wider conflict on Monday as both sides exchanged fresh attacks and President Donald Trump announced the immediate reinstatement of a naval blockade targeting ships travelling to and from Iranian ports.

In a post on his Truth Social platform, Trump said the United States will be known as “THE GUARDIAN OF THE HORMUZ STRAIT,” and charge cargo ships a 20% fee, or any costs deemed necessary “to do the job of providing safety and security to this very volatile section of the World.”

The blockade will only prevent Iran’s ships and its customers from leaving the waterway, Trump said, while other countries should continue to have “fair and open” access to the Strait of Hormuz.

US blockade previously lifted under framework agreement

Washington had previously lifted its naval blockade in mid-June as part of a framework agreement with Iran, aimed at negotiating a lasting ceasefire.

The US and Israel launched strikes on Iran at the end of February, after which Tehran restricted access to the strategically important Strait of Hormuz through threats and attacks on shipping.

The narrow waterway is a key shipping route for global oil and liquefied natural gas supplies, making any disruption a major threat to energy markets.

Under the agreement, Iran committed to doing its “utmost” to ensure safe and toll-free passage for commercial vessels through the strait for 60 days.

However, further attacks on ships in the waterway have since been reported, with Washington blaming Tehran and responding with additional strikes.

Iran’s Islamic Revolutionary Guard Corps (IRGC) said at the weekend that the strait would remain closed until further notice and until the end of US intervention in the region.

Trump rejected that claim on Monday, saying in the Truth Social post that the crucial waterway would remain open “with or without Iran.”

Shipping traffic falls sharply

Shipping traffic through the Strait of Hormuz has dropped sharply in recent days following the latest attacks.

Data from maritime analytics provider Kpler showed that only 14 ships crossed the waterway on Sunday, the lowest figure this month.

Before the conflict began, more than 100 ships passed through the strait on an average day.

Debate over legality of charges

US Secretary of State Marco Rubio said in late June that no country had the right to charge fees for the use of international waters.

The Strait of Hormuz is international waters and does not belong to any single state.

Maritime law experts have long regarded freedom of navigation through such waterways as a key principle of the international order.

Iran targets Bahrain, Kuwait and Jordan

Earlier on Monday, the US Central Command (CENTCOM) said it completed a fourth wave of strikes on military targets in Iran overnight, with dozens of targets at multiple locations hit.

Tehran has responded with missile attacks targeting US-linked sites in Bahrain, Kuwait and Jordan, according to the IRGC and media reports.

Since then, fresh attacks were also reported in south-western Iran on Monday, with two people killed and three others injured in the industrial city of Abadan near the border with Iraq, the ISNA news agency reported.

The deputy governor of Khuzestan province said the strikes took place shortly after midday local time. Iranian authorities blamed the United States for the attacks.

FILE PHOTO - A satellite picture provided by the National Aeronautics and Space Administration (NASA), shows the Arabian Gulf (Persian Gulf), the Strait of Hormuz, and the Gulf of Oman. (is associated with: «Trump renews Strait of Hormuz blockade for Iranian shipping») -/The Visible Earth/NASA/dpa

FILE PHOTO – A satellite picture provided by the National Aeronautics and Space Administration (NASA), shows the Arabian Gulf (Persian Gulf), the Strait of Hormuz, and the Gulf of Oman. (is associated with: «Trump renews Strait of Hormuz blockade for Iranian shipping») -/The Visible Earth/NASA/dpa