ABC News September 27, 2018

Costly F-35 fighter carries out first US combat airstrike

WATCH: News headlines today: Sept. 27, 2018

The costly F-35 fighter jet has carried out its first-ever U.S. combat airstrike, a major milestone for the advanced stealth fighter that is the costliest U.S. military fighter ever manufactured.

The airstrike occurred in Afghanistan and involved a Marine F-35B "Lightning II" that had taken off from the U.S. Navy amphibious ship USS Essex currently operating in the East Arabian Sea.

No further details on the target were provided in a U.S. Navy press release about the airstrike other than to note that it was "in support of ground clearance operations."

"The strike was deemed successful by the ground force commander," said the press release.

“The F-35B is a significant enhancement in theater amphibious and air warfighting capability, operational flexibility, and tactical supremacy,” said Vice Adm. Scott Stearney, the commander of U.S. Naval Forces Central Command. “As part of the Essex Amphibious Ready Group, this platform supports operations on the ground from international waters, all while enabling maritime superiority that enhances stability and security.”

The Marine Corps is in the process of replacing its AV-8B Harrier jets, which deploy aboard Navy amphibious ships, with the F-35B. Like the Harrier, the Marine variant of the F-35 is also capable of taking off and landing vertically.

The 13th Marine Expeditionary Unit (MEU) is the first Marine unit to deploy with F-35B's on a combat deployment.

Estimated to cost $350 billion, the F-35 program has been the most expensive fighter in U.S. military history.

The Pentagon plans to buy more than 2,600 of the aircraft as it becomes the main fighter aircraft for the Air Force, Navy and Marine Corps. The Air Force will receive most of the aircraft, the Navy version will be specifically designed to take off and land on aircraft carriers.

Lockheed Martin, the defense contractor that makes the F-35, expects that per unit costs of the aircraft will go down more of the aircraft are produced. Currently the Air Force version of the aircraft costs $94 million.

The program has been beset by costly delays mainly involving its advanced technologies.

The fifth-generation fighter includes advanced stealth technology, as well as advanced computers and avionics that enable the aircraft to remain airborne.