Yemen's Houthi movement will expand its targets in the Red Sea region to include US ships, as it vows to keep up attacks after US and British strikes on its sites in Yemen.
Attacks by the Houthis on ships in area since November have impacted companies and alarmed major powers in an escalation of Israel's more than three-month war with Hamas militants in Gaza. The group says it is acting in solidarity with Palestinians.
British and American ships had become "legitimate targets" due to the strikes launched by the two countries on Yemen last week, Nasruldeen Amer, a spokesman for the Houthis, told Al Jazeera on Monday.
"The ship doesn't necessarily have to be heading to Israel for us to target it. It is enough for it to be American," Amer said.
"The United States is on the verge of losing its maritime security."
The Houthis previously said they would only target Israeli ships or those en route to Israel.
In the latest apparent attack, the U.S Central Command said Houthi forces in Yemen struck the US-owned and operated dry bulk ship Gibraltar Eagle with an anti-ship ballistic missile on Monday, although there were no reports of injuries or significant damage.
The vessel's US-based operator Eagle Bulk Shipping said it was hit by an "unidentified projectile" while sailing 160km off the Gulf of Aden. The attack caused a fire in a hold of the vessel, which was carrying steel products, but no injuries, and the ship was continuing on its way, it said.
Earlier in the day, British Maritime Security firm Ambrey said a Marshall Islands-flagged, US-owned bulk carrier was reportedly struck by a missile while transiting near Yemen's port of Aden.
The vessel was assessed not to be Israel-affiliated, according to Ambrey, which also assessed the attack to have targeted US interests in response to the recent strikes on Houthi military positions.
The latest attack suggests that despite the US strikes, the Houthis appear undeterred.
Later on Monday an explosion was heard near Yemen's Hodeidah airport, residents reported. Hodeidah is some distance from Aden, however, and it was not immediately clear what had caused the blast.
Container vessels have been pausing or diverting from the Red Sea that leads to the Suez Canal, the fastest freight route from Asia to Europe. Many ships have been forced to take the longer route via the Cape of Good Hope instead.
Ship-tracking data on Monday showed at least 15 tankers altering course in response to the escalating conflict.
The Houthis have been at war with a Saudi-led coalition in Yemen for years, but have turned their sights on the sea to show support for Palestinian group Hamas.
On Sunday, the US said its fighter aircraft had shot down an anti-ship cruise missile fired by the militants toward a US destroyer. No injuries or damage were reported, it said on X.
Britain said it had no desire to be involved in Red Sea conflict but was committed to protecting free navigation.
"Let's wait and see what happens," Defence Secretary Grant Shapps told Sky News on Monday regarding potential further strikes on Houthi sites.
China also called for an end to attacks on civilian vessels in the Red Sea that have placed Beijing's commercial interests at risk.
With vessels pausing or diverting, some supply lines are being affected.
