This article has been updated with recent developments.

The U.S. military conducted airstrikes using B-2 bombers on weapon depots held by Iran-backed Houthi rebels in Yemen late Wednesday, marking the first use of these stealth bombers against the militia.

Defense Secretary Lloyd J. Austin stated that the operation was directed by President Joe Biden to “further degrade” the Houthis’ capacity to carry out assaults on commercial and military vessels in the Red Sea. The strikes might also serve as a warning to Iran amid escalating tensions in the region, particularly with Israel.

Austin did not specify Iran in his statement. However, he remarked that employing the B-2 bomber—capable of carrying heavy “bunker-busting” munitions—showcased the U.S.’s ability to strike at facilities that adversaries attempt to conceal underground or fortify. “The use of U.S. Air Force B-2 Spirit long-range stealth bombers reflects our global strike capabilities to target such locations when needed, anytime, anywhere,” he stated.

The top defense official noted that these “precision strikes” were aimed at five fortified underground weapons storage sites in regions of Yemen controlled by the Houthis. A separate update from the U.S. Central Command (CENTCOM) based in Tampa, Florida, reported that U.S. Navy units were also involved in the operation. CENTCOM is currently assessing the damage from the strikes but initially found “no indications of civilian casualties.”

The Houthis have intermittently targeted ships in the Red Sea, an essential trade route, for several years. However, there has been a significant rise in attacks on commercial tankers and cargo vessels since the onset of the conflict between Israel and Hamas last year. The Houthis assert that their actions express solidarity with Hamas, which is backed by Iran and shares military resources. The rise in Houthi activities has triggered numerous U.S.-led retaliatory strikes against Houthi positions, including radars, airstrips, missile launch sites, and logistical centers. U.S. forces have also intercepted Houthi drones and missiles directed at Israel.

Mohammed Albasha, an independent security expert focusing on Yemen, mentioned that the B-2 bomber strikes suggest a “shift in U.S. policy” towards a more resolute approach against the group’s destabilizing actions.

Experts on Yemen characterize the Houthis as a multifaceted group encompassing a political movement, military force, and a religious faction. They have been engaged in a civil war since 2014 against a nascent government, supported militarily by Saudi Arabia, the United Arab Emirates, and indirectly by the U.S. and Britain through arms supplies.

Albasha also highlighted that in addition to their maritime aggressions and attacks on Israel, there are growing allegations of Houthi human rights abuses within Yemen. Reports include abductions and forced confessions involving aid workers, U.N. staff, and international diplomatic personnel, leading to prosecutions in Houthi “state security courts.” Human rights organizations have noted the increasing restrictions on women’s rights imposed by the Houthi leadership, which aims to implement a strict form of Zaydism, a variant of Shia Islam.

The ongoing conflict between Israel and Hamas in Gaza, which escalated a year ago following a Hamas attack on Israeli communities, has spilled over into a broader regional crisis. This situation has prompted Israel to launch attacks against Hezbollah militants in Lebanon, whom it accuses of using civilian areas for missile strikes targeting northern Israel. Hezbollah, akin to the Houthis, has vowed to continue its operations against Israel until there is a ceasefire in Gaza. According to Lebanon’s health ministry, over 2,300 individuals have died in Lebanon since last October, with three-quarters of those casualties occurring in the past month. The fighting has resulted in the displacement of around 1.2 million people in Lebanon.