Israel set up a clandestine military outpost in the Iraqi desert to support its air campaign against Iran and launched airstrikes against Iraqi troops who almost discovered it early in the war, people familiar with the matter including U.S. officials said.

Israel built the installation, which housed special forces and served as a logistical hub for the Israeli air force, just before the war started with the knowledge of the U.S., The Caspian Post reports via The Wall Street Journal.

Search-and-rescue teams were positioned there in case Israeli pilots were downed. None have been. When a U.S. F-15 jet fighter was shot down near Isfahan, Iran, the Israelis offered to help, but U.S. forces managed the rescue of two airmen themselves, one of the people said. Israel did carry out airstrikes to help protect the operation.

photo: WSJ

The Israeli base was almost discovered in early March. Iraqi state media said a local shepherd reported unusual military activity in the area, including helicopter flights, and the Iraqi military sent troops to investigate. Israel kept them at bay with airstrikes, one of the people familiar with the matter said.

Israel’s military declined to comment. The Iraqi government at the time condemned the attack, which left an Iraqi soldier dead.

“This reckless operation was carried out without coordination or approval,” Lt. Gen. Qais Al-Muhammadawi, deputy commander of the Joint Operations Command, a central security body, told Iraqi state media in comments about the attack in early March.

In a complaint lodged later in March with the United Nations, Iraq said the attack involved foreign forces and airstrikes, attributing it to the U.S. The U.S. wasn’t involved in the attack, the person familiar with the matter said.

The clash was widely reported in Iraqi and Arab media and generated speculation about the identity of the combatants.

After the initial report from the shepherd, Iraqi soldiers set out in Humvees and drove at dawn toward the site. The group came under intense fire, killing one soldier and wounding two others, Muhammadawi said.

photo: WSJ

Iraqi authorities dispatched two more units from the country’s Counter Terrorism Service, which played an important role in Iraq’s fight with Islamic State, to join a search of the area. It found evidence that military forces had been present in the area.

“It appears there was a certain force on the ground before the strike, supported from the air, operating beyond the capabilities of our units,” Muhammadawi told state media.

An Iraqi government spokesman declined to comment further on the incident or whether it knew of the Israeli base.

The U.S. has carried out multiple strikes in Iraq to protect its own bases and other assets.

Details of the base-and the risks Israel took to establish and protect it-help fill in the picture of how the country managed to fight an air campaign against an enemy around 1,000 miles away.

The base in Iraq allowed Israel to get closer to the battlefield. Israel deployed search-and-rescue teams there so they could respond more quickly if needed for emergency rescue missions, the people familiar with the matter said. Israeli air force special forces, trained to carry out commando operations in enemy territory, were also present on the base, according to one of the people familiar with the matter.

Israel’s air force carried out thousands of strikes against targets in Iran during the five-week campaign.

U.S. forces often set up temporary operational sites in the lead up to military operations, security experts say. A makeshift forward-operating base was set up inside Iran and used in the mission to rescue the U.S. airmen whose plane went down in early April.

photo: WSJ

The U.S. blew up planes and helicopters that got stuck there during the mission.

“It’s normal that before operations you reconnoiter and set up these kinds of locations,” said Michael Knights, the head of research for Horizon Engage, a strategic advisory firm.

The western desert region of Iraq is vast and sparsely populated, making it an ideal location for temporary outposts, Knights said. U.S. Special Forces made use of this area in Iraq as part of operations against Saddam Hussein in 1991 and 2003.

People living in the Iraqi desert have witnessed strange activity over the years, from militant groups like Islamic State to special operations teams, and have learned to stay away, Knights said.

He said locals told him they had spotted unusual helicopter activity there during the current war.

Israeli officials have alluded to covert operations during the war. In early March, the head of the Israeli air force, Tomer Bar, issued a letter to his servicemen.

“These days, fighters from special units of the air force are conducting special missions which could ignite the imagination,” said Bar, who ended his term as air force chief in early May.