Shipping giant Maersk said on Sunday it was suspending the passage of vessels through a key Red Sea strait for 48 hours after Yemeni rebels attacked one of its merchant ships.
The Maersk Hangzhou, a Singapore-flagged, Denmark-owned and operated container vessel en route from Singapore to Port Suez in Egypt, reported being struck by a missile while transiting the Bab al-Mandab Strait.
It appeared to be undamaged in that attack and "was able to continue its transit north", said Maersk, one of the world's largest shipping companies.
It was then attacked by four ships operated by Yemen's Iran-backed Huthi rebels, which "engaged fire in an expected attempt to board the vessel", the Danish shipping company said.
The US military said navy helicopters sank three of the ships while the fourth fled.
"In light of the incident -- and to allow time to investigate the details of the incident and assess the security situation further -- it has been decided to delay all transits through the area for the next 48 hours," said a Maersk statement.
The Huthis have repeatedly targeted vessels in the vital Red Sea shipping lane with strikes they say are in support of Palestinians in Gaza, where Israel is battling militant group Hamas.