American forces have hit more than 800 targets in Yemen during an ongoing air campaign that began six weeks ago against the Houthi militia, the U.S. military said on Sunday.

The military said the targets of the strikes, called Operation Rough Rider, included “multiple command-and-control facilities, air defense systems, advanced weapons manufacturing facilities and advanced weapons storage locations.”

Among the arms and equipment in stockpiles struck by the Americans were antiship ballistic and cruise missiles and drones, the types of weapons that the Houthis have used against ships in the Red Sea, the military said. The details were outlined in an announcement issued by U.S. Central Command, which oversees military operations and forces in the Middle East.

Congressional officials say the campaign has cost well over $1 billion so far, based on closed-door briefings Pentagon officials gave to Congress early this month, just three weeks into the campaign. The New York Times reported in early April on the rapid rate of munitions used in the campaign, a rate that has caused concern among some strategic planners in the U.S. military.

The Houthis have been firing projectiles and launching drones at commercial and military ships in the Red Sea as a show of solidarity with the residents of Gaza and with Hamas, the militant group that controls it. They have been under assault by Israel since Hamas carried out a deadly strike in southern Israel in October 2023 and took hostages.

On March 15, President Trump ordered the U.S. military to begin a continual air campaign against the Houthis, after the Biden administration carried out some strikes. Until Sunday, the U.S. military had not publicly disclosed the number of targets struck in Operation Rough Rider.