By JON GAMBRELL, Associated Press

DUBAI, United Arab Emirates (AP) — A new American airstrike campaign against Yemen’s Houthi rebels appears more intense and more extensive, as the U.S. moves from solely targeting launch sites to firing at ranking personnel as well as dropping bombs in city neighborhoods, an Associated Press review of the operation shows.

The pattern under U.S. President Donald Trump reflects a departure from the Biden administration, which limited its strikes as Arab allies tried to reach a separate peace with the group. It comes after the Iran-backed Houthis threatened to resume attacking “any Israeli vessel” and have repeatedly fired at Israel over the country’s refusal to allow aid into the Gaza Strip.

The Houthi attacks and the response to them have drawn new scrutiny in Washington after security officials in Trump’s administration shared plans for the first round of strikes on the rebels in a group chat that included a journalist. But bombing alone may not be enough to stop the Houthis, whose earlier barrage of missile fire toward the U.S. Navy represented the most intense combat it had seen since World War II.

“Folks that say, ‘We’ll go in there and take out everyone with the last name Houthi and we’ll win.’ The Houthi leadership has been taken out in history in the past, and they are resilient,” retired U.S. Navy Vice Adm. Kevin Donegan said. “They came back and they grew stronger. So this isn’t something that is a one-and-done.”

Meanwhile, concerns are growing over civilians being caught in the middle of the campaign. While the U.S. military has not acknowledged any civilian casualties since the strikes began over a week ago, activists fear strikes may have killed noncombatants already in territory tightly controlled by the Houthis.

“Just because you can’t see civilian harm doesn’t mean it’s not happening,” warned Emily Tripp, the director of the U.K.-based group Airwars, which studies Western airstrike campaigns.

A new, intense U.S. airstrike campaign shakes Yemen

The Trump campaign began March 15. American warships fired cruise missiles while fighter jets flying off of the USS Harry S. Truman aircraft carrier dropped bombs on Houthi-controlled areas of Yemen, a nation on the southern edge of the Arabian Peninsula that is the Arab world’s poorest.

“No terrorist force will stop American commercial and naval vessels from freely sailing the Waterways of the World,” Trump said in a social media post announcing the campaign, days after his administration reimposed a “foreign terrorist organization” designation on the Houthis.

So far, the Houthis say the airstrikes have killed 57 people.

That’s just over half the 106 people the Houthis’ secretive leader, Abdul Malik al-Houthi, claimed the U.S. and U.K. killed during all of 2024. He provided no breakdown of combatants versus noncombatants. Houthi fighters often aren’t in uniform.

Al-Houthi said the two countries launched over 930 strikes last year. The U.S.-based Armed Conflict Location & Event Data Project, known as ACLED, has recorded 305 strikes. The discrepancy between the figures could not be immediately reconciled, though the Houthis could be counting individual pieces of ordnance launched, rather than a single event with multiple bombs used, as ACLED does. The rebels also have exaggerated details in the past.

Between March 15 to March 21, ACLED reported 56 events. The campaign also has seen the highest number of events in a week since the American bombing campaign began on Yemen during the Israel-Hamas war.

Trump administration officials have touted the differences between their strikes and those carried out under President Joe Biden.

“The difference is, these were not kind of pin prick, back and forth, what ultimately proved to be feckless attacks,” Trump’s national security adviser, Mike Waltz, told ABC’s “This Week” on March 16. “This was an overwhelming response that actually targeted multiple Houthi leaders and took them out.”

Waltz has also claimed key members of Houthi leadership, including their “head missileer,” have been killed. The Houthis have not acknowledged any losses in their leadership.

There are indeed clear differences, said Luca Nevola, the senior analyst for Yemen and the Gulf at ACLED. Under Biden, the focus appeared to be on mobile launchers for missiles and drones, then infrastructure, he said. Trump is targeting urban areas more intensely, judging from the number of strikes on cities so far.

“It’s very likely that somehow the Trump administration is pursuing a decapitation strategy,” Nevola added.

The Trump administration is also allowing the U.S. military’s Central Command, which oversees Mideast operations, to launch offensive strikes at will, rather than having the White House sign off on each attack as under Biden. That will mean more strikes.

Israel, which has repeatedly been targeted by Houthi missile fire and drones, including Thursday, also launched four rounds of airstrikes in 2024 and another in January.

Less transparency, growing concerns about civilians being harmed

During the Biden administration, Central Command offered details to the public on most strikes conducted during the campaign. Those details often included the target struck and the reason behind it.

Since the start of the new campaign, however, there’s been no similar breakdown.

Donegan, the retired vice admiral, praised that strategy during a recent call hosted by the Jewish Institute for National Security of America. “You don’t tell the enemy what you’re going to do, and you don’t tell them what you’re not going to do.”

But that also means the Houthis’ description of targets is the only one that’s public. They’ve claimed two attacks targeted an under-construction cancer clinic in the city of Saada, as well as private homes and crowded city neighborhoods. There’s been no effort so far from the U.S. military to either dispute that or offer evidence to support strikes on those targets.

“It’s an extremely complicated information environment in Yemen,” Tripp, of Airwars, said. “The Houthis have extensive restrictions on (activists) and operations, media and press.”

Even so, some information can be gleaned from Houthi-released footage. One strike around Saada that the Houthis say killed a woman and four children included missile debris. Serial numbers on the fragments correspond to a contract for Tomahawk cruise missiles, an AP examination of the imagery showed. That corresponded to an assessment separately made by Airwars.

Including that Saada strike, Airwars believes it is likely that at least five U.S. strikes in the new Trump campaign that have hurt or killed civilians, based off of videos and photos from the site, Houthi statements and other details.

The U.S. military declined to answer questions regarding possible civilian casualties but said the “Houthis continue to communicate lies and disinformation.”

“CENTCOM won’t provide details on strikes and locations until the operation has concluded, and there is no additional risk to U.S. personnel or assets involved,” it added, using an acronym for Central Command. “At the direction of the president, CENTCOM continues to conduct strikes across multiple Iran-backed Houthi locations every day and night to restore freedom of navigation and restore American deterrence.”

Houthi attacks started over the Israel-Hamas war

From November 2023 — weeks after the Israel-Hamas war began — until January of this year, the Houthis targeted over 100 merchant vessels with missiles and drones, sinking two and killing four sailors.

The rebels said the campaign in the Red Sea, the Gulf of Aden and the Bab el-Mandeb Strait connecting the two waterways was carried out in solidarity with Hamas. It stopped with the ceasefire reached in that war in January.

The attacks greatly raised the Houthis’ profile as they faced economic problems and launched a crackdown targeting any dissent and aid workers at home amid Yemen’s decadelong stalemated war.

Since the ceasefire ended, the Houthis have not resumed their attacks on shipping in the vital corridor for cargo and energy shipments moving between Asia and Europe. Still, overall traffic remains sharply reduced.

A European Union naval force has been patrolling the Red Sea and escorting ships, as well as taking Houthi fire. However, the vast majority of Houthi attacks toward military targets has been pointed at U.S. Navy vessels.

More US forces move into Mideast as Yemen’s future in question

The U.S. airstrikes have kept up a daily tempo since beginning March 15. Meanwhile, the USS Carl Vinson and its carrier strike group is to transit into the Middle East.

That, along with the Truman, will likely give the American military two places to launch aircraft since it hasn’t immediately appeared that any strikes came from bases in other Mideast nations — where public sentiment remains strongly with the Palestinians in the Israel-Hamas war.

The U.S. military also may be bringing additional firepower, as radio transmissions from B-2 stealth bombers and flight-tracking data suggested the U.S. Air Force is moving a number of the aircraft to Diego Garcia in the Indian Ocean.

Satellite images from Planet Labs PBC analyzed by the AP showed three B-2s parked Wednesday at Camp Thunder Cove on the island. That would provide a closer location for the long-range bombers to launch that’s still far outside of the range of the rebels — and avoids using allies’ Mideast bases.

In October, the Biden administration used the B-2 to target what it described as underground bunkers used by the Houthis.

But the future of Yemen itself remains in question. The Houthis broadly maintain control over the capital of Sanaa and the country’s northwest. Yemen’s exiled government is part of a fractious coalition that for now appears unable to wrest any control back from the rebels. Meanwhile, Saudi Arabia and the United Arab Emirates, which launched a war 10 years ago against the Houthis, have pushed for peace talks as fighting appears broadly frozen on the ground.

“The United States can hurt the Houthis, it can weaken them,” wrote Gregory D. Johnsen, a Yemen expert at the Arab Gulf States Institute in Washington, “but without effective ground troops — either its own or someone else’s — it will not be able to eliminate their capabilities.”