Israel built the installation, ​which housed special forces and served as a ​logistical hub for the Israeli air force, with the ⁠knowledge of the US just before the start of ​the US-Israeli war against Iran, the newspaper said.

It also included ​search-and-rescue teams positioned to assist any downed Israeli pilots, the Journal said.

Reuters could not independently verify the report.

There was no immediate ​response from the Israeli prime minister’s office to a ​Reuters request for comment.

The base was almost discovered in early March after ‌Iraqi ⁠state media said a local shepherd reported unusual military activity, including helicopter movements in the area.

Iraqi troops were dispatched to investigate, but Israeli forces used air strikes to keep ​them at a ​distance and ⁠prevent the site from being discovered, the paper said, citing one of the sources.

The ​Journal cited a complaint filed with the United ​Nations ⁠later in March in which Iraq said the attack involved foreign forces and airstrikes and attributed it to the US.

⁠The ​WSJ cited a person familiar with ​the matter as saying the United States was not involved in the ​attack.