"We're not looking to expand this. The Houthis have a choice to make and they still have time to make the right choice, which is to stop these reckless attacks," White House spokesman John Kirby said.

Attacks by the Houthis on ships in the Red Sea have affected companies and alarmed major world powers. The Houthis say they are acting in solidarity with Palestinians.

(Reporting by Steve Holland, Writing by Jasper Ward; Editing by Caitlin Webber)