"The Persian Gulf Strait Authority has already introduced a new framework requiring ships to obtain transit authorisation and pay tolls before sailing," said Lloyd's List, the industry journal which provides news and intelligence on shipping and maritime trade.

It added that "ships are required to submit detailed records of ownership, insurance, crew details and intended transit route", citing a form sent by the authority.

On Tuesday, Iranian English-speaking broadcaster Press TV said Iran had built a "system to exercise sovereignty over the Strait of Hormuz" and that ships passing through the strait were sent "regulations" from the email [email protected].

The new mechanism comes as US President Donald Trump paused a short-lived operation seeking to force open the Strait of Hormuz to merchant ships, citing hopes that a deal with Iran was imminent.

Tehran has choked the vital waterway, through which a fifth of the world's oil normally passes, since the start of the Middle East war in late February.

Iran has repeatedly indicated that it seeks to impose a new reality in the Strait of Hormuz, exacting tolls on transiting ships and sharing the revenues with Oman.

The United States has imposed its own blockade on Iranian ports in the Gulf, and flare-ups in the waterway have dampened hopes for a quick deal to permanently end the war.

Overnight clashes in the Gulf saw Iranian forces launch missiles, drones and small boats at three US warships, the US Central Command said, adding that none were hit.

American forces destroyed the incoming threat and retaliated against land bases in Iran.

Iran's own central military command countered that the clash had erupted when US vessels targeted an Iranian civilian tanker heading towards the Strait of Hormuz.