MSC, the world's largest carrier of ocean container cargo, said on Tuesday all cargo bound for ports in the Gulf will be offloaded at the nearest safe seaport due to ongoing hostilities in the Middle East following U.S. and Israeli attacks on Iran.

The move, known as an "End of Voyage" declaration, also applies to empty containers that have been released for loading with cargo and are intended for export to the ports in the Gulf, Geneva-based MSC said in a customer advisory.

A mandatory surcharge of $800 per container will apply to all affected shipments, without exception, to cover deviation costs, MSC said.

"MSC sincerely regrets the necessity of this decision, which arises from exceptional circumstances beyond its control," the company said.

Customers will assume responsibility for the container at the discharge port, said Lars Jensen, CEO of container shipping-focused consultancy Vespucci Maritime, on LinkedIn. That means shippers are responsible for finding alternate transportation and paying local port fees, he said.

The hostilities have caused vessels including oil tankers and container ships to back up at the critical Strait of Hormuz chokepoint, sparking worries that global fuel prices could soar.

As of Sunday, 158 container ships were present in the Middle East, including the Gulf of Oman, the Arabian Sea and the Gulf, representing just 2.1% of the current active container ship fleet, according to data from Drewry, a London-based maritime consultancy.

MSC and Ocean Network Express, known as ONE, earlier this week stopped accepting cargo bound for the affected areas in the Middle East. Industry experts warned that the hostilities would trigger cascading delays and disruptions that could take weeks to play out as operators reroute ships, containers and other assets.

"Container shipping has less to lose from the Iran conflict compared to other shipping sectors, but it cannot escape disruption and higher costs," said Simon Heaney, Drewry's senior manager of container research, in a report on Tuesday.

-Reporting by Lisa Baertlein; Editing by Jamie Freed/Reuter