SEOUL, South Korea (AP) — North Korea on Monday issued its latest threat, warning of an indiscriminate “pre-emptive nuclear strike of justice” on Washington and Seoul, this time in reaction to the start of huge U.S.-South Korean military drills.

Such threats have been a staple of young North Korean leader Kim Jong Un since he took power after his dictator father’s death in December 2011. But they spike especially when Washington and Seoul stage what they call annual defensive springtime war games. Pyongyang says the drills, which started Monday and run through the end of April, are invasion rehearsals.

The North’s powerful National Defense Commission threatened strikes against targets in the South, U.S. bases in the Pacific and the U.S. mainland, saying its enemies “are working with bloodshot eyes to infringe upon the dignity, sovereignty and vital rights” of North Korea.

“If we push the buttons to annihilate the enemies even right now, all bases of provocations will be reduced to seas in flames and ashes in a moment,” the North’s statement said.

Responding to the North’s threat, South Korean Defense Ministry spokesman Moon Sang Gyun said Monday that North Korea must refrain from a “rash act that brings destruction upon itself.”

This year’s war games will be the largest ever staged, involving 300,000 South Korean and 17,000 U.S. troops. South Korea’s Yonhap news agency, citing military sources, reported that the allies will work on drills for precision attacks on North Korean leadership and its nuclear and missile arsenal in the event of war.

A pre-emptive large-scale military strike that would end the authoritarian rule of the Kim dynasty is highly unlikely. There is also considerable outside debate about whether North Korea is even capable of the kind of “strikes” it threatens.