Updated

South Korean media are quoting a lawmaker as saying that North Korean hackers may have stolen highly classified military documents, including U.S.-South Korean wartime "decapitation strike" plans against the North.

Democratic Party Rep. Lee Cheol-hee cited unidentified defense officials as saying the hackers stole the plans last year. Neither Lee nor Defense Ministry officials responded to attempts late Tuesday to seek comment.

If confirmed, such a hack would be a major blow for South Korea at a time when its relations with North Korea are at a low point. The South has taken an increasingly aggressive stance toward the North's belligerence amid back-and-forth threats of war between North Korea and Washington.

Lee was quoted as saying the plans included blueprints for attacks to eliminate North Korean leader Kim Jong Un.