LONDON ¨C North Korean hackers have conducted a global cyber espionage campaign to try to steal classified military secrets to support Pyongyang¡¯s banned nuclear weapons program, the United States, Britain and South Korea said in a joint advisory on Thursday.

The hackers ¡ª dubbed Anadriel, or APT45, by cybersecurity researchers ¡ª have targeted or breached computer systems at a broad variety of defense or engineering firms, including manufacturers of tanks, submarines, naval vessels, fighter aircraft, and missile and radar systems, the advisory said.

¡°The authoring agencies believe the group and the cyber techniques remain an ongoing threat to various industry sectors worldwide, including but not limited to entities in their respective countries, as well as in Japan and India,¡± the advisory said.

It was co-authored by the FBI, the U.S. National Security Agency (NSA) and cyber agencies, Britain¡¯s National Cyber Security Center (NCSC), and South Korea¡¯s National Intelligence Service (NIS).

¡°The global cyber espionage operation that we have exposed today shows the lengths that DPRK state-sponsored actors are willing to go to pursue their military and nuclear programs,¡± said Paul Chichester at the NCSC, a part of Britain¡¯s GCHQ spy agency, using the initials of North Korea¡¯s official name, the Democratic People¡¯s Republic of Korea.

Internationally isolated North Korea has a long history of using covert hacking teams to steal sensitive military information.

In August last year, one elite group of North Korean hackers had successfully breached systems at NPO Mashinostroyeniya, a rocket design bureau based in Reutov, a small town on the outskirts of Moscow.

As was the case with that hack, APT45 ¡ª a part of North Korea¡¯s Reconnaissance General Bureau intelligence agency ¡ª used common phishing techniques and computer exploits to trick officials at the firms they were targeting into giving away access to their internal computer systems, Thursday¡¯s advisory said.