– Designs for many of the nation's most sensitive advanced weapons systems have been compromised by Chinese hackers, according to a report prepared for the Pentagon and officials from government and the defense industry.

Among more than two dozen major systems whose designs were breached are programs critical to U.S. missile defenses and combat aircraft and ships, according to a previously undisclosed section of a confidential report prepared by the Defense Science Board for Pentagon leaders.

Experts warn that the electronic intrusions gave China access to advanced technology that could accelerate the development of its weapons systems and weaken the U.S. military advantage in a future conflict.

The Defense Science Board, a senior advisory group composed of government and civilian experts, did not accuse the Chinese of stealing the designs. But senior military and industry officials with knowledge of the breaches said the vast majority were part of a widening Chinese campaign of espionage against U.S. defense contractors and government agencies.

The significance and extent of the targets help explain why the Obama administration has escalated its warnings to the Chinese government to stop what Washington sees as rampant cybertheft.

In March, the advisory panel warned in the public version of its report that the Pentagon is unprepared to counter a full-scale cyberconflict. The list of compromised weapon designs is contained in a confidential version provided to the Washington Post.

Some of the weapons form the backbone of the Pentagon's regional missile defense for Asia, Europe and the Persian Gulf. The designs included those for the advanced Patriot missile system; an Army system for shooting down ballistic missiles, known as the Terminal High Altitude Area Defense; and the Navy's Aegis ballistic missile defense system.

Also identified in the report are vital combat aircraft and ships, including the F/A-18 fighter jet, the V-22 Osprey, the Black Hawk helicopter and the Navy's new Littoral Combat Ship, which is designed to patrol waters close to shore.

Also on the list is the most expensive weapons system ever built — the F-35 Joint Strike Fighter. The 2007 hack of that project was reported previously.

China, which is pursuing a long-term, comprehensive strategy to modernize its military, is investing in ways to overcome the U.S. military advantage — and cyberespionage is seen as a key tool in that effort, the Pentagon noted this month in a report to Congress. For the first time, the Pentagon specifically named the Chinese government and military as the culprits behind intrusions.