Iran is determined to win international recognition of its control over the Strait of Hormuz and ability to levy fees on ​ships entering or leaving the Gulf even if it has to do so by force, two senior Iranian sources said.

Under this month’s interim deal with the U.S. to end their three-month conflict, ‌Iran agreed to let ships pass through the Strait for 60 days without charge. But it believes the wording of the agreement allows it to keep control of which ships may pass and which route they take through the narrow waterway, Reuters reported.

It is also determined to secure lasting formal acceptance of this control once the interim phase expires, and its negotiators will not move to other areas of dispute in ongoing peace talks with Washington until that has been agreed, the sources said.

If the interim deal ends ​without being extended, Iran would start charging ships for passage in mid-August, though it has not yet laid out any list of what fees it will charge or how. Iran closed the Strait ​when the war began and Iranian officials have said authorities charged some vessels navigation or other fees to leave the Gulf.

Any lasting Iranian ⁠control over the Strait of Hormuz, with formalities and fees for ships, would add costs, delays and risks to all shipping through a waterway that before the war transported a fifth of global energy supplies plus other critical ​goods.

Passage through the Strait was never previously subject to fees and Tehran’s position runs directly counter to U.S. interpretations of the interim Memorandum of Understanding agreed on June 17, and to Washington’s stance on what the ultimate ​post-war arrangements will be.

U.S. President Donald Trump said last week that there would be no tolls charged for passage through the Strait unless Washington decided to impose them itself. Secretary of State Marco Rubio said during a meeting with Gulf states that no country had the right to block shipping or impose fees or tolls for passage through an international waterway.

Iran interprets the interim deal as meaning it can maintain control over all passage through the Strait, though without collecting fees during the interim phase of the ​deal, and that while it has to discuss arrangements with Gulf states, it is not obliged to reach an agreement with them, the sources said.

Oman stretches along the southern coast of the Strait and Iran is ​planning talks with the sultanate to define transit paths through the waterway, Tehran said on Monday.

However, Iran shot at four ships over the weekend that tried to traverse the Strait on the Omani side without first getting Iranian permission, triggering a brief ‌but intense ⁠exchange of fire with the United States.

One of the senior officials said Iran would not let the situation return to the pre-war status quo. Instead, it believes new arrangements must govern Hormuz including Iran choosing how vessels enter and leave the Strait, holding the right to deny entry to any it suspects of threatening Iranian security, and charging fees for compulsory services it provides.

Iran is ready to impose its demands on the Strait through force if there is no agreement by other countries to accept its terms, the official added, saying Tehran would not back down even if it led to renewed – and intensified – confrontation ​with the U.S.

The second senior Iranian official said that ​having survived what Tehran had seen as its ⁠biggest potential threat – a war with the U.S. and Israel – Iran believed it had a “historic opportunity” to secure a long-term advantage.

Ship-owning countries would eventually accept Iranian management of the Strait because of the growing cost of the dispute, and Washington would accept it to ensure uninterrupted global energy supplies, the official added.

However, Iran may be overplaying its hand and miscalculating how far Washington would be willing to accept what would be seen as an enormous concession, said ​Ali Ansari, professor of modern ⁠history at St Andrews University, read the report.

“The prospect of this conflict reigniting is much higher than people think because neither side thinks they’ve lost,” he said.

Neither Iran nor the U.S. is a signatory of the U.N. Convention on the Law of the Sea that designates Hormuz as an international strait, although Oman, which stretches along its southern coast, is.

While the waterway is split between the territorial waters of Iran and Oman, its status as an international strait under the convention requires ⁠free passage.

The convention ​is widely regarded, including by the U.S., as customary international law.

It is also the agreement under which Iran could claim its territorial ​waters extend 12 miles rather than the mere 3 miles off its shore under other maritime conventions, said Chris O’Flaherty, a former British navy captain and specialist in naval warfare and law. The Strait of Hormuz is just over 20 miles wide at its narrowest ​point.

“This is an intensely political matter in which most people think international law is settled. However, Iran has decided to challenge that,” O’Flaherty said.