BEIJING - China dismissed accusations it stole F-35 stealth fighter plans as groundless on Monday, after documents leaked by former U.S. intelligence contractor Edward Snowden on a cyber attack were published by a German magazine.

The Pentagon has previously acknowledged that hackers had targeted sensitive data for defence programmes such as the F-35 Joint Strike Fighter, but stopped short of publicly blaming China for the F-35 breach. The Pentagon and the jet's builder, Lockheed Martin Corp , had said no classified information was taken during the cyber intrusion.

"The so-called evidence that has been used to launch groundless accusations against China is completely unjustified," Foreign Ministry spokesman Hong Lei told reporters.

Hong said the "complex nature" of cyber attacks makes it difficult to pinpoint the relevant attacker, adding that China wanted to work with other countries to prevent hacking.

"According to the materials presented by the relevant person, some countries themselves have disgraceful records on cybersecurity," Hong added.

Snowden's 2013 revelations of the broad reach of the National Security Agency's (NSA) spying programme sparked international outrage.

Lockheed Martin is producing the F-35 for the U.S. military and allies in a $399 billion project, the world's most expensive weapons programme.

It is intended to deliver advanced stealth capabilities, improved manoeuvrability and high-tech sensors, but the programme has struggled with delays and budget overruns.