It warned customers to prepare for significant disruption.

The move is in response to attacks on shipping in the Gulf region by Iranian-backed Houthi militants in Yemen, in support of Palestinian Islamist group Hamas fighting Israel in Gaza.

The Red Sea is the shortest route from Asia to Europe via the Suez Canal, and is used by roughly one third of global container ship cargo.

Redirecting ships around Africa can add about 10 days to journey times and up to $1 million extra in fuel for every round trip.

In a statement, Maersk said the situation is "constantly evolving and remains highly volatile", but confirmed all its ships would reroute until further notice.

On Thursday (January 4), Maersk ordered four container vessels that had already passed through the Suez Canal to turn back and start the long journey around Africa.

The United States last month launched a multinational operation to try to safeguard commerce in the Red Sea.

But many shipping companies and cargo owners are still choosing to divert vessels, amid continued attacks.