Two crew members have been killed in a Houthi missile strike on a cargo ship off southern Yemen, US officials say - the first deaths the group's attacks on merchant vessels have caused.
The Barbados-flagged True Confidence had been abandoned and was drifting with a fire on board after the strike.
It was hit in the Gulf of Aden at about 09:30 GMT, managers said.
The Houthis say their attacks are to support the Palestinians in the war between Israel and Hamas in Gaza.
In a statement, the Iran-backed group said the True Confidence's crew had ignored warnings from Houthi naval forces.
The British embassy in Yemen said the sailors' deaths were the "sad but inevitable consequence of the Houthis recklessly firing missiles at international shipping" and insisted the attacks had to stop.
Six crew members were also injured, a US official told the BBC's US partner CBS.
The vessel had a crew of 20, comprising one Indian, four Vietnamese and 15 Filipino nationals. Three armed guards - two from Sri Lanka and one from Nepal - were also on board.
The attack happened about 50 nautical miles (93km) south-west of the Yemeni city of Aden, a spokesman for the ship's owners and managers said in a statement.
Following the attack, Houthi-run Al-Masirah TV reported on Wednesday evening that two US-led air strikes had targeted the international airport in the Houthi-controlled Red Sea port city of Hudaydah.
The True Confidence had been hailed over VHF radio by a group calling itself the "Yemeni navy" and told to change course, according to the United Kingdom Maritime Trade Operations (UKMTO) agency.
Nearby vessels then reported a loud bang and a large plume of smoke.
The UKMTO said the True Confidence was hit and suffered damage, and that naval vessels from a US-led international maritime coalition were supporting the ship and its crew.
The EU's Maritime Security Centre-Horn of Africa (MSCHOA) also said that rescue and salvage operations were under way.
The Houthis claimed in their statement that the True Confidence was an "American ship", but the spokesman said the vessel had "no current connection with any US entity".
A US State Department spokesperson said Washington would continue to hold the Houthis accountable for their attacks and called on governments around the world to do the same.
"The Houthis have continued to launch these reckless attacks with no regard for the well-being of innocent civilians who are transiting through the Red Sea and now they have unfortunately and tragically killed innocent civilians," Matthew Miller said.
UK Foreign Secretary Lord Cameron said: "We condemn the Houthis' reckless and indiscriminate attacks on global shipping & demand they stop."
"We will continue to stand up for freedom of navigation and back our words with actions," he posted on social media.
The True Confidence is owned by True Confidence Shipping SA, which is registered to an address in Liberia, and operated by Third January Maritime Ltd in Greece, both firms said in a statement.
However it had previously been owned by US-based Oaktree Capital Management, AP reported. Oaktree declined to comment to AP.
The bulk carrier had been sailing to Jeddah in Saudi Arabia from Lianyungang in China, tracking data showed, and was carrying a cargo of steel products and trucks, a spokesman said.
After nearly four months of sustained drone and missile attacks by the Houthis against shipping passing through the Gulf of Aden and Red Sea a fatal attack was perhaps, as the British Embassy stated, inevitable.
The US-led naval taskforce in the region has been shooting down as many of these missiles and drones as it can but there are simply too many for them to destroy every single one.
The Houthis seem to have an inexhaustible supply of them. This calls into question the efficacy of the US-led campaign of airstrikes that has been targeting Houthi launch sites, ammo depots and Command and Control posts.
Now that the Houthi attacks have turned deadly there are bound to be calls to step up retaliation against them, expanding the range of targets inside Yemen. But this in turn risks escalation in a region already tense due to the humanitarian situation in Gaza.
The Houthis say their attacks are in support of the Palestinians. The US, UK, Bahrain and several other nations have demanded an immediate end to the Houthi attacks on shipping.
On Tuesday, US forces shot down a ballistic missile and three drones launched from Yemen at the destroyer USS Carney, followed by three anti-ship missiles and three sea drones.
Meanwhile, on Monday the Indian navy helped put out a fire on board the container ship MSC Sky II, which its operator said had been hit by a missile that caused a small fire and no injuries.
On Sunday, a Belize-flagged cargo ship, Rubymar, sank in the Red Sea two weeks after hit by missiles fired by Houthis. It was the first ship to have been sunk since the Houthi attacks began in November.
The Rubymar was near the Bab al-Mandab Strait, which connects the Gulf of Aden with the Red Sea, when it was attacked. The crew was rescued and the vessel began slowly taking on water.
It was carrying a cargo of 21 tonnes of ammonium nitrate fertiliser, which the US military said presented an environmental risk in the Red Sea.
BBC News
