The Philippines said Tuesday it would ask "friendly countries" to help secure the release of nine Filipino sailors being held by Yemen's Huthi rebels.

The Iran-backed Huthis released footage on Monday of crew members missing after attacks on the Eternity C and Magic Seas cargo ships, claiming in an accompanying statement to have "rescued" the mariners.

Last week, Human Rights Watch said the rebels were unlawfully detaining the crew and that their attacks on shipping amounted to war crimes. The United States has accused the Huthis of kidnapping.

Philippine Foreign Undersecretary Eduardo De Vega confirmed the Huthis were holding nine Filipino seafarers.

"I do not want to use the term hostage. At least we know they are alive," he told AFP. 

"We're not going to talk directly with the Huthis. We're going to seek help from friendly countries," he added.

The European Union's Operation Aspides naval task force told AFP that 15 of the 25 people onboard the Eternity C were still missing — with four presumed dead.

Cosmoship, the owner of the Eternity C, urged the Huthis on Tuesday to release its crew members "at the earliest opportunity."

In a statement, the company expressed relief that "ten of our missing crew members, as well as one of the vessel's security guards (11 in total), are alive and appear to be receiving care", after viewing the footage released by the rebels.

"We continue to work through every available channel to support their continued care and to facilitate their safe and swift return home to their families," it added.

Red Sea attacks

The Philippines Department of Migrant Workers, which has overseen efforts to bring the survivors home, did not immediately respond to a request for comment.

The Huthis sank the Magic Seas and Eternity C in separate Red Sea attacks this month, after a temporary hiatus in their campaign against maritime traffic.

The Huthis launched attacks on ships in the trade route soon after the start of the Gaza war in October, claiming solidarity with Palestinians.

The sinking of the Magic Seas was their first attack since late last year, with the Eternity C facing a similar fate soon after. 

In its statement, the Huthis said they rescued 11 crew members, including two injured, and also recovered a body from aboard the ship before it sank.

The video appeared to show the moment the mostly Filipino crew were pulled from the sea wearing life jackets.

A man the Huthis said was an electrician was shown lying in bed and speaking in English. Aspides had said a Russian electrician onboard the ship had lost his leg.

De Vega said one of the nine Filipinos had suffered an unspecified injury, and that one of the non-Filipino personnel was also injured.

Two weeks ago, eight other Filipino crew members who survived the Eternity C attack were flown back to the Philippines. All 17 Filipino seafarers from the Magic Seas have likewise been flown home.

Previously, the Huthis held the mostly Filipino crew of the Galaxy Leader merchant ship for more than a year, before releasing them in January.

Filipino sailors make up as much as 30 percent of the world's commercial shipping force. The nearly $7 billion they sent home in 2023 accounted for about a fifth of the remittances to the archipelago nation.