By Alex Jensen

SEOUL

South Korea's military leadership threatened Saturday to bring about "the destruction of the Pyongyang regime", as North Korea warned it was preparing for a pre-emptive strike against the largest ever military drills involving the South and the United States.

Accusing the allies of planning their own attack, the General Staff of the North's Korean People's Army declared that it was just "waiting for the dignified Supreme Command to issue an order to launch a pre-emptive strike of justice on the aggressors".

The statement, carried by Pyongyang's official KCNA news agency, also threatened to "liberate" the South with a Korean-style blitzkrieg offensive.

North Korea's Supreme Commander and head of state Kim Jong-un cautioned earlier in the week that his country had the ability to fix nuclear warheads upon long-range missiles.

Pyongyang's rhetoric has become steadily more aggressive since the United Nations imposed strengthened sanctions against the reclusive state for its nuclear test and long-range rocket launch in January and February, respectively.

But the North has been particularly irked by the start of the weeks-long joint military exercises in the South last Monday.

Saturday's warning from North Korea highlighted a landing drill underway in South Korea's eastern port city of Pohang -- also involving Australia and New Zealand as part of the United Nations Command, which fought on the South's side in the unresolved 1950-53 Korean War.

Seoul and Washington have long maintained that their annual exercises are defensive.

"If the North continues to make provocations despite the stern warnings made by our military, it is inevitable for us to roll out a strict response that may lead to the destruction of the Pyongyang regime," South Korea's Joint Chiefs of Staff said in a statement, according to local news agency Yonhap.