At least 42 U.S. military aircraft have been lost or damaged since the start of the war with Iran, according to a recent analysis that compiled news reports and officials’ statements to tally losses.

The Congressional Research Service report comes as lawmakers push Pentagon leaders for more clarity on timelines, costs and outcomes pertaining to Operation Epic Fury.

Pentagon acting comptroller Jules Hurst testified to Congress this month that the estimated cost of military operations in Iran had reached $29 billion.

The figure includes equipment repair and replacement costs but does not account for damage to U.S. military bases in the Middle East that came under retaliatory attack by Iran, Hurst said. Joint American-Israeli strikes Feb. 28 against Tehran started the war.

During the conflict, the U.S. has lost 24 MQ-9 Reaper drones, according to the Congressional Research Service. The drones cost about $30 million apiece and can carry as many as 16 Hellfire missiles.

The report also noted that several U.S. aircraft were lost or damaged during search-and-rescue operations after an F-15E fighter jet was shot down over Iran in April.

In addition to the fighter jet, the U.S. lost an A-10 Thunderbolt II and two MC-130J Commando II special operations aircraft, which were intentionally destroyed on the ground in Iran during the operation.

One search-and-rescue helicopter, an HH-60W Jolly Green II, also sustained damage from small-arms fire in the mission.

Early in the war, a KC-135 refueling tanker flying in friendly airspace in Iraq crashed, killing all six crew members aboard. Another tanker was involved and made an emergency landing, according to the report.

The cause of the crash is still under investigation, but initial intelligence reports suggested that the pilots may have been trying to evade anti-aircraft fire from Iran-backed militias, according to recent reporting from The Atlantic.

U.S. Central Command has disputed those early intelligence reports, and the Air Force-led investigation is likely to conclude that the crash was an “avoidable mishap” in congested airspace, The Atlantic said.

Other aircraft that the report says were damaged or lost during Operation Epic Fury include:

Three F-15E Strike Eagle fighters shot down by friendly fire over Kuwait.

Five KC-135 refueling tankers parked at Prince Sultan Air Base in Saudi Arabia that were damaged during an Iranian missile and drone attack.

One F-35A Lightning II fighter aircraft damaged by Iranian ground fire.

One E-3 Sentry aircraft damaged while parked on an unprotected taxiway at Prince Sultan Air Base.

One MQ-4C Triton drone, which reportedly crashed in a mishap.