The attack by Houthi rebels against a civilian merchant ship came as the White House threatened a counter-attack.
ADVERTISEMENTYemen's Houthi rebels killed three seafarers from the Philippines and injured three others on Wednesday in a major escalation of tensions in the Red Sea.
The US Central Command said in a statement that an anti-ship ballistic missile from a Houthi-controlled area in Yemen hit the M/V True Confidence, a Barbados-flagged, Liberian-owned bulk carrier operating in the the Gulf of Aden.
After the missile hit, the crew abandoned the ship and deployed lifeboats. A US warship and the Indian navy were on the scene and tried to assist in rescue efforts.
Two aerial photos released by the US military showed the the ship's bridge and cargo ablaze.
The attack came after the ship had been hailed over radio by men claiming to be the Yemeni military, officials said. The Houthis have been hailing ships over the radio in the Red Sea and the Gulf of Aden since beginning their attacks, with analysts suspecting the rebels want to seize the vessels.
The Philippines' Migrant Workers Department confirmed the deaths and the number of wounded from the attack. They also called for "continued diplomatic efforts to de-escalate tensions and to address the causes of the current conflict in the Middle East".
The Houthis have launched attacks since November over Israel's war on Hamas in the Gaza Strip, with US beginning an airstrike campaign in retaliation since January.
Despite more than a month and a half of US-led airstrikes, the Houthis have remained capable of launching significant attacks. They include the strike last month on a cargo ship carrying fertiliser, the Rubymar, which sank on Saturday after drifting for several days, and the downing of an American drone worth tens of millions of dollars.
It was unclear why the Houthis targeted the True Confidence. The ship had previously been owned by Oaktree Capital Management, a Los Angeles-based fund that finances vessels on instalments. Oaktree declined to comment.