A drone and speedboat attack off Yemen killed four seafarers on a Liberian-flagged, Greek-operated bulk carrier, an official with knowledge of the matter said on Tuesday, the second incident in a day, following months of calm.

Traffic in the Red Sea, a key waterway for oil and commodities, has dropped since Yemen’s Houthi militia aligned with Iran began targeting ships in 2023 in what it called solidarity with Palestinians under assault in Israel’s war in Gaza.

The deaths on the Eternity C, the first involving shipping in the Red Sea since June 2024, take to eight the total of seafarers killed in the Red Sea attacks.

One more injured crew died on board after the attack, a source with knowledge of the matter said, speaking on condition of anonymity.

The Houthis have not commented on the Eternity C, but hours earlier claimed responsibility for a strike on another Liberia-flagged, Greek-operated bulk carrier, the MV Magic Seas, off southwest Yemen on Sunday, saying the vessel sank.

“After several months of calm, the resumption of deplorable attacks in the Red Sea constitutes a renewed violation of international law and freedom of navigation,” IMO Secretary-General Arsenio Dominguez said on Tuesday.

The U.S. State Department condemned the “unprovoked Houthi terror attack on the civilian cargo vessels MV Magic Seas and MV Eternity C”, as demonstrating the threats the Houthis posed to freedom of navigation and regional security.

Washington “will continue to take necessary action to protect freedom of navigation and commercial shipping,” it added in a statement.

The Eternity C’s operator, Cosmoship Management, was not immediately available to comment.

Eternity C, with 21 Philippine nationals and a Russian making up a crew of 22, was adrift and listing after the attack with sea drones and rocket-propelled grenades fired from manned speed boats, maritime security sources told Reuters.

Greece was in diplomatic talks with Saudi Arabia over the incident, sources said, as two maritime security firms, including Greece-based Diaplous, prepared to mount a rescue mission for the crew trapped on Eternity C.

An official with Aspides, the European Union’s mission assigned to help protect Red Sea shipping, also said at least two other crew were injured. Earlier, Liberia’s shipping delegation told a U.N. meeting that two crew were killed.

The Houthis released a video they said depicted their attack on the Magic Seas, including the Mayday call, explosions, and the vessel’s ultimate submersion. Reuters could not independently verify the footage.

The vessel’s manager said the information about the sinking could not be verified.

But Joshua Hutchinson, managing director of maritime security firm Ambrey, told Reuters it had a response vessel in the area and confirmed the Magic Seas had gone down.

All crew on the Magic Seas were rescued by a passing merchant vessel and arrived safely in Djibouti on Monday, Djibouti authorities said.

Since November 2023, the Houthis have disrupted commerce by launching hundreds of drones and missiles at vessels in the Red Sea, saying they were targeting ships linked to Israel.

While the Houthis struck a ceasefire with Washington in May, the militia has vowed to keep attacking ships it says are connected with Israel.

“Just as Liberia was processing the shock and grief of the attack against Magic Seas, we received a report that Eternity C again has been attacked … causing the death of two seafarers,” Liberia’s delegation told a session of the International Maritime Organization.

‘ELEVATED RISKS’

Both vessels attacked were part of commercial fleets whose sister vessels have called at Israeli ports over the past year.

“The pause in Houthi activity did not necessarily indicate a change in underlying intent,” said Ellie Shafik, head of intelligence with the Britain-based maritime risk management company Vanguard Tech.

“As long as the conflict in Gaza persists, vessels with affiliations, both perceived and actual, will continue to face elevated risks.”

The Philippines has urged its seafarers, who form one of the world’s largest groups of merchant mariners, to exercise their right to refuse to sail in “high-risk, war-like” areas, including the Red Sea after the latest strikes, its department of migrant workers said.

Shipping traffic through the region has shrunk about half from normal levels since the first Houthi attacks in 2023, said Jakob Larsen, chief safety and security officer with shipping association BIMCO.

“This reduction in traffic has persisted due to the ongoing unpredictability of the security situation,” Larsen said. “As such, BIMCO does not anticipate the recent attacks will significantly alter current shipping patterns.”

Monday’s attack on Eternity C, 50 nautical miles southwest of Yemen’s port of Hodeidah, was the second on merchant vessels in the region since November 2024, an official at Aspides said.

On Monday, Israel’s military said it had struck Houthi targets at three Yemeni ports and a power plant, in its first attack on Yemen in a month.

The Houthis say their attacks are an act of solidarity with Palestinians in Gaza where Israel’s military assault since late 2023 has killed more than 57,000 people, Gaza authorities say.

The Israeli assault has unleashed a hunger crisis, internally displaced the entire population of Gaza and spurred accusations of genocide at the International Court of Justice and of war crimes at the International Criminal Court.

Israel denies the accusations.

The latest bloodshed in the decades-old Israeli-Palestinian conflict was triggered in October 2023, when Palestinian Hamas militants attacked Israel, killing 1,200 and taking about 250 hostages, Israeli tallies show.