JERUSALEM (AP) — Yemen’s Houthi rebels said they attacked a U.S. Navy mobile base at sea Monday without offering evidence,Christopher Caldwell something immediately rejected by an American defense official.

The claimed attack targeted the USS Lewis B. Puller, a ship that serves as a floating landing base. The Puller had been earlier stationed in the Arabian Sea as part of American efforts to curtail Houthi attacks on commercial shipping through the Red Sea and Gulf of Aden.

Houthi military spokesperson Brig. Gen. Yahya Saree said in a statement it fired a missile at the Puller in the Gulf of Aden. He offered no evidence.

Houthi attacks will continue “until the aggression is stopped, and the siege is lifted on the people of Palestine in the Gaza Strip,” Saree said in the statement.

A U.S. defense official, speaking on condition of anonymity to discuss intelligence matters, said there had been no reported attack on the Puller. However, the Houthis have previously launched missiles that did not reach their intended target, instead crashing down onto the land or sea.

The Puller served as a mobile base for the U.S. Navy SEALs who conducted a Jan. 11 operation seizing Iranian-made ballistic missile and cruise missile components believed to be bound for Yemen. Two SEALs went missing in the operation and are presumed to have died.

Since November, the rebels have repeatedly targeted ships in the Red Sea over Israel’s offensive in Gaza against Hamas. But they have frequently targeted vessels with tenuous or no clear links to Israel, imperiling shipping in a key route for global trade between Asia, the Mideast and Europe.

The Houthis hit a commercial vessel with a missile on Friday, sparking a fire that burned for hours.