The US military said Thursday that it had destroyed four Houthi nautical drones and two aerial ones over the Red Sea off Yemen.
The Iran-backed Houthis have launched scores of drones and missiles at commercial vessels in the Red Sea and Gulf of Aden since November, describing the attacks as being in support of Palestinians during the Israel-Hamas war in the Gaza Strip.
The United States and its allies, particularly Britain, have responded with an increased naval presence to defend shipping in the vital waterway and with retaliatory strikes on Houthi targets.
The US Central Command (CENTCOM) said in a statement Thursday night that its forces had "destroyed four Iranian-backed Houthi uncrewed surface vessels (USV) in the Red Sea and two uncrewed aerial systems (UAS) over the Red Sea" in the past 24 hours.
CENTCOM said the day before that it had destroyed "one ground control station and one command and control node" in a Houthi-controlled area of Yemen.
This week, a merchant ship whose hull was breached in an earlier Houthi attack, the M/V Tutor, was believed to have sunk in the Red Sea after its crew was evacuated, according to a maritime security agency run by the British navy.
A Filipino sailor aboard the vessel was killed in the attack.
A Sri Lankan crew member on another ship, the M/V Verbena, was seriously injured in a separate attack, and the vessel had to be abandoned.
US State Department spokesman Matthew Miller condemned those attacks in a statement and said Washington would "continue to take necessary action to protect freedom of navigation and commercial shipping."
He also called on the Houthis "to release all detainees, including the United Nations, diplomatic, and non-governmental organization staff they detained earlier this month."
The Houthis earlier this month arrested a number of people they claimed were part of a US-Israeli spy network, adding that those held worked under "the cover of international organizations and UN agencies."
The heads of six United Nations agencies and three international NGOs subsequently issued a joint call for the release of their staff, with UN rights chief Volker Turk dismissing the spying accusations as "outrageous."
The Houthis are engaged in a long-running civil war that has triggered one of the world's worst humanitarian crises. More than half of the population is dependent on aid in the Arabian Peninsula's poorest country.