An advanced US 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 tells Reuters.

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 Houthi movement in Yemen on Thursday, including Sanaa International Airport, and Houthi media said at least six people were killed.

After the Israeli airstrikes the top UN 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 paralyse 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.”