Chinese hackers have gained access to the designs of many of the nation's most sensitive advanced weapons systems, according to a report.

The compromised weapons designs include, among others, advanced Patriot missile system, the Navy's Aegis ballistic missile defense systems, the F/A-18 fighter jet, the V-22 Osprey, the Black Hawk helicopter and the F-35 Joint Strike Fighter, said USA Today.

The confidential report was prepared by the Defense Science Board, a senior advisory group of government and civilian experts.

It does not accuse the Chinese of stealing the designs, but says that the designs of more than two dozen systems were compromised, the Washington Post reported.

An alleged breach of U.S. systems was noted in a public report issued by the advisory panel in January, but the section of the report listing the compromised weapons system remained classified until Tuesday. The public version had warned that the Pentagon is unprepared to counter a full-scale cyber-conflict.

The Chinese government has insisted that it does not conduct ­cyber-espionage on U.S. agencies or companies, and government spokesmen often complain that Beijing is a target of U.S. cyberattacks, the Post notes.