US officials say a new round of missiles targeting an American warship in the Red Sea has been fired from a region of Yemen controlled by Houthi fighters.
The USS Mason, a destroyer, launched countermeasures and was not hit in Saturday's strike.
Three US warships in the Red Sea detected the missiles, the US military said, amid rising tensions with the Iran-allied group.
"The Mason once again appears to have come under attack in the Red Sea, again from coastal defence cruise missiles fired from the coast of Yemen," Admiral John Richardson, chief of naval operations, announced on Saturday in Baltimore.
US officials initially said that surface-to-surface missiles had been fired at the USS Mason, USS Nitze and USS Ponce off the coast of Yemen starting around 19:30 GMT, though it was unclear how many.
If confirmed, the missile launches would be the third attack in about a week targeting the Mason and other US ships.
Earlier this week, the Mason, sailing in international waters off Yemen's coast, used unspecified countermeasures against incoming missiles, a military official said on the condition of anonymity.
The attempted missile strikes is the most serious escalation yet of US involvement in Yemen's civil war.
The conflict has killed an estimated 6,800 people, wounded more than 35,000 and displaced at least three million since an Arab coalition assembled by Saudi Arabia launched military operations last year.
US officials say the US wants to avoid getting embroiled in yet another war in the Middle East.
On Thursday, the US navy launched five Tomahawk cruise missiles at three mobile radar sites in Houthi-controlled territory along Yemen's Red Sea coast, after the fighters fired rockets at the USS Mason twice in four days.
The US military insists these moves are taken out of self-defence. The Houthis have denied conducting the attacks.
Though the US is providing logistical support to the Arab coalition battling the Houthis, Thursday's launches marked the first time the US has taken direct action against the group.
But the US strikes earlier this week did not take out Houthi missiles, and though the radar destruction makes it harder to aim the weapons, officials say the fighters could still use spotter boats or online ship-tracking websites to find new targets.
Rise of the Houthis
Officially known as Ansarallah (Partisans of God), the Houthis began as a theological movement that preached tolerance and peace in the early 1990s.
A religious group affiliated with the Zaydi sect of Shia Islam, they maintained a stronghold in the northern province of Saada.
The group's rise began to pick up momentum in August 2014 when thousands of its supporters protested in the streets of the Yemeni capital Sanaa, urging the government to step down.
Among other demands, Houthi leader Abdulmalek al-Houthi requested that fuel subsidies, which had been cut significantly in late July, be reinstated.
After the Houthis' swift rise to power culminating in the overthrow of President Abd-Rabbu Mansour Hadi, the Arab coalition stepped in on March 25, 2015, and began air strikes in an effort to stop their advance.
Source: Agency News