The U.S. military launched cruise missile strikes on Thursday to knock out three coastal radar sites in areas of Yemen controlled by Houthi forces, retaliating after failed missile attacks this week on a U.S. Navy destroyer, U.S. officials said.

The strikes, authorized by President Obama, represent Washington’s first direct military action against suspected Houthi-controlled targets in Yemen’s conflict.

Still, the Pentagon stressed the limited nature of the strikes, aimed at radar that enabled the launch of at least three missiles against the U.S. Navy ship USS Mason on Sunday and Wednesday.

“These limited self-defense strikes were conducted to protect our personnel, our ships and our freedom of navigation,” Pentagon spokesman Peter Cook said.

An official identified the areas in Yemen where the radar were located as near Ras Isa, north of Mukha and near Khoka.

The failed missile attacks on the USS Mason appeared to be part of the reaction to a Saudi-led strike on mourners gathered in the capital Sanaa, which claimed at least 140 people.

The Pentagon warned against any future attacks.

“The United States will respond to any further threat to our ships and commercial traffic, as appropriate,” Cook said.