Shipowners will not resume transit through the Strait of Hormuz ​for weeks until they are confident that the U.S.-Iran ‌deal is "material", the chief executive of Japan's Mitsui O.S.K. Lines told the Financial Times in an interview published on Tuesday.

The Iran war that began on February 28 ​, with U.S.-Israeli strikes, largely stopped shipping through the transit route for around a fifth of the world's oil and liquefied natural gas supply, along with products such as aluminium and urea.

Mitsui O.S.K., one of Japan’s big three shipping firms, has a ​fleet of more than 900 vessels, including bulk carriers, tankers and ferries.

"What will have to come in place is not just a simple agreement between ​the relevant countries, but it has to be material and translated ​into the real situations in the Strait of Hormuz, so that shipping lines ‌can ⁠make themselves comfortable to go through," Mitsui O.S.K.'s Jotaro Tamura told FT before U.S President Donald Trump announced a deal to end the war in Iran.

"Given the experiences in the last couple of months, I think it’s ​reasonable to assume ​that it ⁠may take at least a couple of weeks or if not a month," Tamura told the paper.

Mitsui ​O.S.K. did not immediately respond to a Reuters ​request for ⁠comment.

The agreement between Washington and Tehran, which was being finalised, had not changed Tamura's view, the FT report said.

President Donald Trump said in a Truth Social ⁠post ​that ships loaded with oil are ​starting to move out of the strait, "going along the Southern 'Highway,' which is totally safe, secure, ​and pristine".