Britain and the United States on Thursday said they had imposed sanctions on key Houthi figures to protect maritime security in the Red Sea. British Foreign Secretary David Cameron said the restrictions “reinforce our clear message to the Houthis in recent weeks,” promising to target those behind the “unacceptable and illegal actions” against shipping. Four key Houthi figures involved in the attacks will be subject to UK asset freezes, arms embargoes and travel bans, a statement from Cameron’s department read. Targets of the sanctions include the commander of the Houthi naval forces and the Ho…