A US airstrike on an important oil port held by Yemen’s Houthi rebels killed more than 70 people and wounded many others, the Iranian-backed rebel group said Friday, marking a major escalation in the military campaign President Donald Trump launched against the faction last month.

The overnight strike on the Ras Isa port sent massive fireballs billowing skyward and turned tanker trucks into burning wrecks. It was the first American attack on a Houthi-controlled oil facility in the new U.S. bombing campaign. It also came just before the resumption of negotiations in Rome between the U.S. and Iran over Tehran’s rapidly advancing nuclear program, which Washington has linked to its attacks in Yemen.

The U.S. is targeting the Houthis because of the group’s attacks on shipping in the Red Sea, a crucial global trade route, and on Israel. The Houthis are the last militant group in Iran’s self-described “Axis of Resistance” that is capable of regularly attacking Israel.

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The port is a major hub for incoming fuel shipments that power areas of Yemen held by the Houthis, and analysts say the airstrike could seriously affect daily life there.

The Houthis, who said the attack killed at least 74 people and wounded 171 others, aired graphic footage of the aftermath on their al-Masirah satellite news channel, showing corpses strewn about the port and smashed tanker trucks. They denounced the strike as a “completely unjustified aggression.”

“It targets a vital civilian facility that has served the Yemeni people for decades,” the group said in a statement.

U.S. Central Command declined to answer any questions about possible civilian casualties but referred to a statement in which it said “this strike was not intended to harm the people of Yemen.”

“U.S. forces took action to eliminate this source of fuel for the Iran-backed Houthi terrorists and deprive them of illegal revenue that has funded Houthi efforts to terrorize the entire region for over 10 years,” it said in its statement.

A U.S. official said the attack sent a message to those supplying fuel to the Houthis despite sanctions. The official spoke to The Associated Press on the condition of anonymity to provide details not yet made public.

Hours after the U.S. strike, the Houthis launched a missile toward Israel that was intercepted, the Israeli military said. Sirens sounded in Tel Aviv and elsewhere. Meanwhile, the Houthis said they shot down another American MQ-9 Predator drone, which the U.S. official acknowledged.

The port’s strategic significance

The Ras Isa port is a collection of oil tanks and equipment that sits in Yemen’s Hodeida governorate along the Red Sea. It is just off Kamaran Island, which has been targeted by intense U.S. airstrikes in recent days.

Before the Houthis took control of Yemen’s capital, Sanaa, in 2014 and sent the government into exile, oil from the country’s energy-rich Marib governorate moved through Ras Isa for export. But since the Houthis don’t control that region, the port now serves as an import hub for gasoline, diesel and liquefied petroleum gas that help power those parts of Yemen the Houthis control.

A deadly escalation of Trump’s Yemen campaign

The new U.S. operation against the Houthis under Trump appears more extensive than attacks on the group were under President Joe Biden, an AP review found. The new campaign started after the rebels threatened to begin targeting “Israeli” ships again over Israel blocking aid from entering the Gaza Strip.

From November 2023 until this January, the Houthis targeted more than 100 merchant vessels with missiles and drones, sinking two of them and killing four sailors. That has greatly reduced the flow of trade through the Red Sea corridor, which typically sees $1 trillion of goods move through it. The Houthis also launched attacks targeting American warships without success.

Assessing the toll of the month-old U.S. airstrike campaign has been difficult because the military hasn’t released information about the attacks, including what was targeted and how many people were killed. The Houthis, meanwhile, strictly control access to attacked areas and don’t publish complete information on the strikes, many of which likely have targeted military and security sites.

The Ras Isa port airstrike is the deadliest known attack yet in the month-old campaign. The actual cost in lives is hard to assess, said Luca Nevola, the senior analyst for Yemen and the Gulf at the Armed Conflict Location & Event Data Project, a think tank.

“Since they are targeting civilian areas, there’s a lot more victims. But it’s also difficult to assess how many because the Houthis are releasing these umbrella statements that cover all the victims … or tend to stress only the civilian victims,” Nevola said.

Further complicating the situation is the U.S. strikes hitting military targets, said Mohammed al-Basha, a Yemen expert at the Basha Report risk advisory firm. He pointed to an American attack that Trump highlighted online with black-and-white strike footage, which might have killed about 70 fighters.

“Although the Houthis claimed it was a tribal gathering, they neither released any footage nor named a single casualty, strongly suggesting the victims were not civilians but affiliated fighters,” al-Basha said. “However, the overnight strike on the Ras Isa Fuel Port marks the first mass-casualty incident the Houthis have openly acknowledged and publicized.”

The AP analyzed satellite images of the port provided by Planet Labs PBC that showed destroyed oil tanks and vehicles, and what appeared to be oil leaking into the Red Sea.

Wim Zwijnenburg, an analyst with the Dutch peace organization PAX, said it appeared at least three fuel storage tanks had been destroyed and that oil had leaked from mooring pipelines.

The U.S. airstrikes continued overnight into early Saturday, with the Houthis reporting them in Yemen’s al-Jawf, Sadaa and Sanaa governorates.

The U.S. accuses a Chinese company of aiding Houthi attacks

A U.S. State Department spokesperson, Tammy Bruce, accused a Chinese commercial satellite image provider, Chang Guang Satellite Technology Co. Ltd., of “directly supporting Iran-backed Houthi terrorist attacks on U.S. interests.”

During a briefing with reporters, Bruce did not elaborate in detail. But she acknowledged a report by The Financial Times that quoted anonymous American officials saying the company linked to the People’s Liberation Army has provided images allowing the rebels to target U.S. warships and commercial vessels traveling through the Red Sea corridor.

Bruce said “Beijing’s support” of the satellite company … “contradicts their claims of being peace supporters.”

Responding to a question about the allegation, Chinese Foreign Ministry spokesperson Lin Jian said Friday: “I am not familiar with the situation you mentioned.” However, he insisted China is seen as urging countries “to make more efforts conducive to regional peace and stability.”

“Since the escalations in the Red Sea situation, China has been playing a positive role in de-escalating the situation,” Lin said. “Who is promoting talks for peace and deescalating the tensions, and who is imposing sanctions and pressure?”

The company didn’t respond to request for comment. The U.S. Treasury sanctioned it in 2023 for allegedly providing satellite images to the Russian mercenary force the Wagner Group as it fought in Ukraine.

It remains unclear whether Chang Guang is linked to the Chinese government. The U.S. government in the past has used images taken by American commercial satellite companies to share with allies, like Ukraine, to avoid releasing its own top-secret pictures.