DUBAI, United Arab Emirates (AP) — The U.S. military has deployed B-2 stealth bombers to attack the underground bunkers they use Yemen’s Houthi rebels Early Thursday saw a significant escalation in the American response to rebel attacks on shipping routes in the Middle East, which also appeared to be a warning to Iran.

Although it was not immediately clear how much damage the strikes caused, the attack appeared to be the B-2’s first use in combat in years and the first time the flying wing had attacked targets in Yemen.

With the announcement of the attacks against the Houthis, who have been attacking ships in the Red Sea corridor for months, they are over the Israel-Hamas war In the Gaza Strip, US Defense Secretary Lloyd Austin made a point of issuing a warning that was likely also heard in Tehran.

“This was a unique demonstration of the United States’ ability to target facilities that our adversaries want to keep out of reach, no matter how deeply buried, fortified or fortified,” Austin said.

Iran, the Houthis’ main benefactor, has done this targeted ballistic missile attacks on Israel twice last year. The B-2 would be used in each American attack on secured Iranian nuclear facilities like Natanz or Fordo, as it is the only aircraft in service that can drop this GBU-57, known as the Massive Ordnance Penetrator.

Iran had no immediate comment on the attack on Thursday. Its foreign minister has visited Arab countries ahead of an expected Israeli retaliation over the Oct. 1 rocket attack in Tehran.

The Houthis’ satellite news channel al-Masirah reported airstrikes around the Yemeni capital Sanaa, which the group has held since 2014. They also reported attacks around the Houthi stronghold of Saada. They did not provide any immediate information about damage or casualties.

Austin said the B-2 bombers attacked “five fortified underground weapons depots in Houthi-controlled areas of Yemen.” Both he and the US military’s Central Command did not provide an immediate assessment of the damage caused. However, Central Command said it believed no civilians had been killed.

The Red Sea has become a battleground for shippers since the Houthis began their campaign against ships passing through the waterway that once carried $1 trillion worth of cargo annually.

Since the war in Gaza began in October 2023, the Houthis have attacked more than 80 commercial vessels with missiles and drones seized a ship And Two were sunk in the campaign Four sailors also died. Other missiles and drones were either intercepted by a US-led coalition in the Red Sea or failed to reach their targets, which included Western military ships.

The rebels claim they are targeting ships with ties to Israel, the US or the UK to force an end to Israel’s campaign against Hamas in Gaza. However, many of the ships attacked have little or no connection to the conflict, including some bound for Iran.

The Houthis also continue to fire rockets at Israel and have fired US military MQ-9 Reaper drones. In response, the rebels threatened new attacks Israel’s ground invasion of Lebanon and it is Killing of Hezbollah leader Hassan Nasrallah.

About 1,200 people were killed and 250 others were taken hostage in Hamas’ first attack on Israel on October 7, 2023, which triggered the war. Since then, Israeli military operations have killed over 42,000 Palestinians in the Gaza Strip, hundreds more in the West Bank and over 2,300 people in Lebanon. Meanwhile, the fight is moving ever closer to an all-out regional war.

The sites named by the Houthis on Thursday correspond to known underground bases of the rebels, who have been locked in a stalled war with a Saudi-led coalition since 2015 that has decimated the Arab world’s poorest country.

The Houthis have renovated tunnels that once housed Scud missiles when Yemen was still ruled strongman Ali Abdullah Salehaccording to an analysis by the International Institute for Strategic Studies in April. These sites include the al-Hafa and Jebel Attan military bases, the former presidential house and the Yemeni state television compound in Sanaa, wrote analyst Fabian Hinz.

Hinz added that the Houthis also appeared to have built their own large network of tunnels near Saada.

“The fact that after the Houthis agreed, the Houthis began building large new facilities Ceasefire with the Saudi-led coalition suggests the group is focused on consolidating itself and strengthening its military capabilities,” he wrote. Iran also relies on a network of underground missile bases.

The nuclear-capable B-2, first used in the 1999 Kosovo war, is rarely used in combat by the U.S. military because each aircraft is worth about $1 billion. Bombs were also dropped in Afghanistan, Iraq and Libya. The planes are based at Whiteman Air Base, Missouri, and typically conduct long-range strikes from there, although some B-2s were in Australia in September.

The US last used the B-2 in combat against it in 2017 Targets of the terrorist militia “Islamic State” in LibyaIn a mission in which more than 80 fighters were killed, defense officials said they disrupted possible attacks by militant forces in Europe.

The B-2’s deployment to Yemen comes just two days after UN special envoy Hans Grundberg warned that Yemen’s frozen war could intensify again amid Middle East wars The Houthis capture UN and aid workers in an internationally criticized raid.

“This cycle of retaliation is drawing Yemen deeper into the regional conflict and endangering its hopes for peace and stability,” Grundberg said Tuesday. “Furthermore, it distracts from the urgent need to address Yemen’s own internal crisis.”