A Liberian-flagged cargo ship attacked by Yemen’s Houthi rebels sank Wednesday in the Red Sea, and a European naval force in the Mideast said only six of the 25 people who were on board have been rescued.

The attack on the Eternity C, which also killed at least three of the crew, represents the most serious assault carried out by the Houthis in the crucial maritime trade route where $1 trillion in cargo once passed through annually.

From November 2023 to December 2024, the Houthis targeted more than 100 ships with missiles and drones in a campaign the rebels describe as supporting Palestinians in the Gaza Strip during the Israel-Hamas war. The Iranian-backed rebels stopped their attacks during a brief ceasefire in the war. They later became the target of an intense weekslong campaign of airstrikes ordered by U.S. President Donald Trump.

The attack on the Eternity C, as well as the sinking of the bulk carrier Magic Seas in another attack Sunday, raise new questions about the Red Sea’s safety as ships had slowly begun returning to its waters. Meanwhile, a new possible ceasefire in the Israel-Hamas war — as well as the future of talks between the U.S. and Iran over Tehran’s battered nuclear program — remain in the balance.

“We are now with grave concern seeing an escalation in the Red Sea with attacks on two commercial ships earlier this week by Ansar Allah, resulting in civilian loss of life and casualties as well as the potential for environmental damage,” warned United Nations special envoy Hans Grundberg, using another name for the rebels.

6 of 25 on board have been rescued

A statement from the European Union naval mission in the Red Sea said the crew of the ship included 22 sailors, among them 21 Filipinos and one Russian, as well as a three-member security team. Those rescued were five Filipinos and one Indian.

Three people also were killed during the hourslong attack on the ship, the EU force said, and their nationalities were not immediately known.

The armed rebels had attacked the ship with rocket-propelled grenades and small arms, later using two drones and two drone boats carrying bombs to strike the vessel, the EU force said. The Eternity C sank at 7:50 a.m. Wednesday, it added.

The ship, flagged out of Liberia but owned by a Greek firm, likely had been targeted like the Magic Seas over its firm doing business with Israel. Neither vessel apparently requested an escort from the EU force.

The U.S. military has two aircraft carriers in the Mideast, the USS Nimitz and the USS Carl Vinson, but both likely are in the Arabian Sea, far from the site of the attacks. There are two American destroyers believed to be operating in the Red Sea. However, the ships attacked had no U.S. ties and a ceasefire between the Houthis and America announced after the bombing campaign earlier this year still appears to be holding.

Brig. Gen. Yahya Saree, a Houthi military spokesman, claimed the attack in a prerecorded message Wednesday night as the EU force acknowledged it was still searching for those onboard with private industry rescuers.

The Houthis later released footage of them launching missiles at the Eternity C. The bridge appeared heavily damaged by the attack and oil leaked from the vessel. The ship took on water from holes along its waterline before sinking beneath the waves, the rebels chanting: “God is the greatest; death to America; death to Israel; curse the Jews; victory to Islam.”

The Houthis released a similar video after their attack on the tanker Sounion in August 2024 and on Tuesday from their attack on the Magic Seas.