The Biden administration on Wednesday returned Yemen-based Houthi rebels to the list of terrorist groups, US officials said.
Officials said their designation on the list, which hits the Iran-linked group with tough sanctions, was aimed at cutting off funding and weapons the Houthis have used to attack or hijack ships in vital Red Sea shipping lanes. .
The Houthi attacks have disrupted global trade, stoked inflation fears and deepened concerns that fallout from the Israel-Hamas war could destabilize the Middle East.
"These attacks fit the definition of terrorism," one of three administration officials who briefed reporters before the announcement said on condition of anonymity.
Their re-listing as terrorists comes after US and British warplanes, ships and submarines last week launched dozens of airstrikes against Houthi targets, who control the most populated parts of Yemen.
The US military carried out its latest strike on Tuesday against Houthi ships, two US officials told Reuters.
The Houthi militia movement, which says the attacks on merchant ships are aimed at supporting the Palestinians in Israel's war in Gaza, has prompted a "strong and effective response".
The attacks are part of a broader response to the Gaza conflict by the so-called Axis of Resistance - including the Houthis along with Palestinian militants Hamas, Lebanon-based Hezbollah and Iraqi Shiite militias - with ties to US adversary Iran .