North Korean hackers have reportedly stolen top-secret US-South Korea military documents - including details of a plan to assassinate Kim Jong Un.
The South Korean Defence Ministry revealed hackers "presumed to be North Koreans" stole 235GB worth of documents while responding to a freedom of information request by Minjoo Party (Democratic Party) politician Rhee Cheol Hee.
The hackers, according to South Korean newspaper The Chosun Ilbo, obtained the documents by breaking into the military's intranet and related networks in August and September last year.
Despite South Korean authorities previously claiming nothing of significance had leaked, reports have suggested Pyongyang gained access to OPLAN 5015 - South Korea's combined operations with the United States in a conflict with North Korea.
The plan - reportedly devised in 2015 - is said to include a detailed strategy for the "decapitation" of the North Korean leadership in the event of a full-scale war, according to the Yonhap news agency.
The Defence Ministry had only listed 53GB worth of the stolen data - about 10,700 documents or 22.5% of the total amount.
Along with OPLAN 5015, documents included OPLAN 3100 - the South's strategy for dealing with its neighbours localised provocations.
A contingency plan for the Special Warfare Command in the event of sudden changes in North Korea or a major provocation was also among the documents known to have been leaked.
Rhee told the paper: "I can't reveal further details because they are a military secret."
According to reports, the leaked files also include personnel reports of South Korean and American military officers and top secret minutes of meetings about South Korea-US military drills.
The leaks also contain information on military installations and power plants in South Korea.
According to Yonhap News, Pyongyang has denied responsibility for any cyber-attacks, criticising Seoul for "fabricating" the claims.
The latest development comes amid months of growing tensions between the US and North Korea over its refusal to end its nuclear weapons programme.
It has resulted in an ongoing war of words between Donald Trump and Kim Jong Un.
At the weekend, the US leader said efforts with Pyongyang had broken down and that "only one thing will work".
The swipe came after he threatened to "totally destroy" North Korea during his UN General Assembly address, insisting "the United States is ready, willing and able (to act), but hopefully this will not be necessary".
The North Korean leader, who has continued to add to tensions with continued nuclear missile tests, addressed Mr Trump's previous comments and insisted "a frightened dog barks louder".