Dec 27 (Reuters) - An advanced U.S. military

anti-missile system was used in Israel to try to intercept a

projectile for the first time since President Joe Biden placed

the system in Israel in October, a source familiar with the

matter told Reuters on Friday.

The THAAD, or Terminal High Altitude Area Defense system,

was used to try to intercept a projectile from Yemen sometime

during the last 24 hours, and an analysis would determine its

success, said the source who spoke on condition of anonymity.

The Pentagon did not immediately respond to a request for

comment.

Israel struck multiple targets linked to the Iran-aligned

Houthi movement in Yemen on Thursday, including Sanaa

International Airport, and Houthi media said at least six people

were killed.

Houthis have repeatedly fired drones and missiles towards

Israel in what they describe as acts of solidarity with

Palestinians in the Gaza Strip.

In October, Biden placed the THAAD system, built by Lockheed

Martin ( LMT ), in Israel along with about 100 U.S. soldiers to

help defend the country. THAAD is a critical part of the U.S.

military's layered air defense systems and added to Israel's

already formidable anti-missile defenses.

After the Israeli airstrikes the top U.N. aid official in

Yemen, Julien Harneis, said on Friday that Sanaa airport was

civilian infrastructure used by international aid workers to

access the north of Yemen, warning: "If that airport is

disabled, it will paralyze humanitarian operations."

"Parties to the conflict have an obligation to ensure that

they are not striking a civilian target," he told reporters. "We

don't need to prove we're civilians. They need to prove that

they are hitting a military target. Sanaa Airport has not been a

military target since 2016."

The United Nations says more than half Yemen's population -

some 18 million people - need humanitarian help. Harneis told

reporters that is expected to rise to 19 million next year due

to worsening economic conditions in the country.

He also said airstrikes on Hodeidah port were particularly

concerning as it was "absolutely vital" because Yemen imports

about 80% of its foodstuffs.

"It's a civilian facility, there is no doubt about that, and

the U.N. works to ensure that and any damage to it will lead to

massive suffering for Yemenis," Harneis said.