Danish shipping company Maersk has said it is pausing all journeys through the Red Sea.
The decision comes after a spate of attacks on vessels launched from a part of Yemen controlled by the Houthis – an Iran-backed rebel movement.
The group has declared its support for Hamas and say it is targeting ships travelling to Israel.
The Red Sea is one the world’s most important routes for oil and fuel shipments.
“The recent attacks on commercial vessels in the area are alarming and pose a significant threat to the safety and security of seafarers,” Maersk, one of the world’s biggest shipping companies, wrote in a statement sent to the BBC.
“Following the near-miss incident involving Maersk Gibraltar yesterday and yet another attack on a container vessel today, we have instructed all Maersk vessels in the area bound to pass through the Bab al-Mandab Strait to pause their journey until further notice,” it added.
German transport company Hapag-Lloyd later said it was making a similar move.
The firm owns a ship that recently came under attack, and confirmed later on Friday it was also suspending operations in the area until Monday.
The Bab al-Mandab strait – also known as the Gate of Tears – is a channel 20 miles (32km) wide, and known for being perilous to navigate.
It sits between Yemen on the Arabian Peninsula and Djibouti and Eritrea on the African coast.
It is the route by which ships can reach the Suez Canal from the south – itself a major shipping lane. Avoiding it means vessels must take much longer routes, for example navigating around southern Africa.
About 17,000 ships and 10% of global trade pass through it every year. Any ship passing through Suez to or from the Indian Ocean has to come this way.
Maersk pausing its Red Sea shipping journeys “could not come at a more difficult time”, director general at the Institute of Export & International Trade Marco Forgione said.
“This impacts every link in the supply chain… and will only increase the chances of critical products not making their destinations in time for Christmas,” he added.
At least two other cargo ships in the strait came under attack on Friday. The US says one was hit with a drone and another by missiles, blaming the Houthis for both attacks.
The Houthis did not confirm the drone strike, but said they did fire missiles at two boats.
The group has controlled parts of Yemen since seizing power from the country’s government in 2014, triggering an ongoing civil war.
Speaking before the announcements by Maersk and Hapag-Lloyd, US national security adviser Jake Sullivan – who is on a trip to the Middle East – said the Houthis were threatening freedom of navigation in the Red Sea, which is vital for oil and goods shipments.
“The United States is working with the international community, with partners from the region and from all over the world to deal with this threat,” he said.
Earlier this month, a US warship shot down three drones fired from Houthi-controlled territory in Yemen after three commercial vessels came under attack in the Red Sea.
Just days before that incident, the US said another warship had captured armed men who had earlier seized an Israeli-linked tanker off Yemen’s coast.
Last month, the Houthis released video footage showing armed men dropping from a helicopter and seizing a cargo ship in the southern Red Sea.
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Shipping firms pause Red Sea journeys over attacks