"The ship doesn't necessarily have to be heading to Israel for us to target it; it is enough for it to be American," Nasruldeen Amer, a spokesperson for the Houthis, told Al Jazeera.
"The United States is on the verge of losing its maritime security."
Amer also said British and American ships had become "legitimate targets" due to the strikes launched by the two countries on Yemen last week.
Attacks on ships since October by the Houthis, who say they are acting in solidarity with Palestinians, have hit commerce and alarmed major powers in a regional escalation of Israel's more than three-month war with Hamas militants in Gaza.
In the latest apparent attack, a U.S.-owned bulk carrier was reportedly struck by a missile near Yemen's port of Aden, causing a fire in a hold but no injuries on board, according to British Maritime Security firm Ambrey.
(Reporting by Muhammad Al Gebaly and Hatem Maher; Editing by Andrew Heavens and Alison Williams)
