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.

The Iran war that began on February 28 with U.S.-Israeli strikes largely stopped shipping through the transit route.

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, according to Reuters.

“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.

The agreement between Washington and Tehran being finalized had not changed Tamura’s view, the FT report said.