(Yonhap) -- North Korea trained Iranian soldiers to blow up Iraqi tanks in 1982 with a motorcycle carrying a liquefied natural gas (LPG) cylinder, Seoul's declassified diplomatic documents showed Sunday.

   Military cooperation between North Korea and Iran started after a bitter eight-year war broke out in 1980 when Iraq invaded Iran, but the documents revealed details on how Pyongyang offered Tehran lethal assistance and equipment at the time.

   The documents, written by the South Korean embassy in Tehran on April 30, 1982, and based on "intelligence from Iranian soldiers," said North Korean Special Forces "trained Iranian troops to destroy Iraqi tanks by driving a motorcycle carrying LPG cylinders into a tank."

   "The anti-tank guerrilla tactic was used in the war," the documents said.

   Japanese-made 90cc or 125cc motorcycles were used for the tactic and an LPG cylinder was designed to explode by a detonation device linked to the motorcycle's fuel tank when it struck the tank, according to the documents.

   The documents were made public on Sunday by Seoul's foreign ministry as part of its annual release of diplomatic documents after 30 years of confidentiality.

   In November 1980, North Korea sent about 60 Special Forces officers to Iran and another 30 officers for T-62 tanks.

   According to the documents, North Korea supplied US$300 million worth of weapons to Iran, including 60 T-62 tanks, surface-to-air and anti-tank guided missiles and multiple rocket launchers, during the eight-year war between Iran and Iraq.