The US military has attacked radar sites in Yemen after a US warship in the Red Sea came under missile attack for the second time within days.
The Pentagon said initial assessments showed that three radar sites involved in the recent missile launches had been destroyed.
It said the targeted sites were on territory controlled by Iranian-backed Houthi rebels.
The Pentagon said the strikes had been authorised by President Barack Obama.
The attack was carried out using Tomahawk cruise missiles fired from the destroyer USS Nitze, according to US officials.
“These limited self-defence strikes were conducted to protect our personnel, our ships, and our freedom of navigation in this important maritime passageway,” Pentagon spokesman Peter Cook said.
“The United States will respond to any further threat to our ships and commercial traffic, as appropriate.”
They came hours after at least one missile was fired at the USS Mason, a guided-missile destroyer, in the Red Sea off Yemen.
The Pentagon said the ship took defensive action and suffered no damage.
On Sunday, two missiles were fired at the USS Mason from the same rebel-held territory.
Both missiles hit the water before reaching the ship, the Pentagon said.
At the time, a Houthi spokesman told the Saba news agency that it had not targeted any warships.
A Saudi-led multinational coalition, supported by the US, is carrying out an air campaign against the Houthi movement.
However, US support for the coalition has come under strain following an air strike on a funeral hall in the capital Sanaa earlier this month that killed at least 140 people.
Washington said it would review its support to “better align with US principles, values and interests”.
The Saudi government has not publicly acknowledged that its planes carried out the strike, but it has launched an inquiry.
It has also said it will facilitate the evacuation of Yemenis injured in the attack who need medical treatment abroad.
The UN says at least 4,125 civilians have been killed and 7,207 injured since the coalition intervened in the conflict between forces loyal to Yemen’s internationally-recognised government and those allied to the Houthis in March 2015.
Yemen conflict: US strikes radar sites after missile attack on ship}