Israel has said that Yemen’s Houthis had seized a British-owned and Japanese-operated cargo ship in the southern Red Sea, describing the incident as an “Iranian act of terrorism” with consequences for international maritime security, Reuters reports.

Last week, the Houthi leader said his forces would make further attacks on Israel and they could target Israeli ships in the Red Sea and the Bab al-Mandeb Strait. There was no immediate comment from the Houthis on Sunday.

Israeli Prime Minister Benjamin Netanyahu’s office said a ship — which it did not name — had been seized and stressed that Israel was not involved in its ownership, operation or the make-up of its international crew.

“There were no Israelis on the ship,” it said. “This is another Iranian act of terrorism that represents an escalation in Iran’s belligerence against the citizens of the free world, with concomitant international ramifications vis-a-vis the security of global shipping routes.”