WASHINGTON, United States (AFP) — The United States on Wednesday conducted multiple B-2 bomber strikes on weapons storage facilities in areas of Yemen controlled by the Iran-backed Houthi rebels, according to the US military and defense department.

“US forces targeted several of the Houthis’ underground facilities housing various weapons components of types that the Houthis have used to target civilian and military vessels throughout the region,” US Defense Secretary Lloyd Austin said in a statement.

The Houthi-run Al Masirah television network reported 15 strikes at dawn on Thursday local time targeting sites north and south of the capital Sanaa, as well as farther north in Saada governorate, a Houthi stronghold.

B-2 bombers conducted precision strikes against five underground weapons storage locations, Austin said, adding that use of the long-range stealth bomber demonstrates “US global strike capabilities to take action against these targets when necessary, anytime, anywhere.”

The US and Britain have repeatedly carried out strikes aimed at curbing the Houthis’ ability to target shipping, but the rebels have continued to attack merchant vessels transiting the Red Sea and Gulf of Aden.

“At the direction of President Biden, I authorized these targeted strikes to further degrade the Houthis’ capability to continue their destabilizing behavior and to protect and defend US forces and personnel in one of the world’s most critical waterways,” Austin said.

The Houthis, part of the “axis of resistance” of Iran-linked groups, have targeted ships they say have connections to Israel since November in what they describe as support for Palestinians during the Israel-Hamas war.

The attacks have seriously disrupted a route which carries 12 percent of global trade, triggering the reprisal strikes by the US and Britain that began in January.

The US Central Command, which is responsible for US forces in the Middle East, said on social media that there were no initial indications of civilian casualties from Wednesday’s mission.

Mohammed al-Basha, a US-based Yemen and Middle East security analyst, said the use of B-2 bombers indicated Washington was taking “a firmer stance” against the Houthis.

“This operation signifies a shift in US policy, indicating a firmer stance against the group’s destabilizing behavior as Washington intensifies efforts to degrade their military capabilities,” Basha said.