U.S. President Donald Trump said Thursday he believes the war involving Iran could end soon, telling reporters he does not expect the conflict to continue much longer.

"I think it's going to end pretty soon. I don't think they can go much longer," Trump said in the Oval Office in a reference to Iran.

Meanwhile, a U.S. official said Thursday that a temporary deal between Iran and Oman would allow ships to pass through the Strait of Hormuz free of charge.

"Any temporary routes will be without any impediments - meaning no approvals or permissions and no tolls or charges," the official said. "The Strait of Hormuz is an international waterway and no party controls the lanes or the ability to transit through them.

Iran currently continues to control the critical waterway, which is normally a key route for the export of oil and liquefied natural gas from the Gulf states.

Tehran is reportedly on the verge of reaching an agreement with Oman regarding shipping through the strait.

With a view to opening the strait, Iran is reported to have proposed a kind of round-trip route: ships could enter the Persian Gulf via a northern route through the strait and leave it again via a southern route along the coast of Oman.

The U.S. is not said to have been involved in the negotiations between the two Gulf states.

This is said to be an interim solution, while the sea mines laid by Iran are cleared.

The dispute over the strait is central to why the war between the U.S. and Iran has recently escalated once again.

Before the outbreak of the war at the end of February, ships were able to pass through the strait unhindered.