North Korea said on Friday it will never sit down with South Korea for talks again, rejecting a vow by the South's President Moon Jae-in to pursue dialog with Pyongyang made the previous day as he pledged to bring in unification by 2045.

The North has protested joint military drills conducted by South Korea and the United States, which kicked off last week, calling them a "rehearsal for war" and has fired several short-range missiles in recent weeks.

The loss of dialog momentum between the North and South and the stalemate in implementing a historic summit between their two leaders last year is entirely the responsibility of the South, a North Korean spokesman said in a statement.

The spokesman repeated criticism that the joint U.S.-South Korea drills was sign of Seoul's hostility against the North.

"As it will be clear, we have nothing more to talk about with South Korean authorities and we have no desire to sit down with them again," the North's spokesman for the Committee for the Peaceful Reunification of the Country said.

The committee is the North's government outfit tasked with managing relationship with the South. The rival Koreas remain technically at war under a truce ending the 1950-53 Korean War. The comments were carried by official KCNA news agency.

Moon and North Korean leader Kim Jong Un have met three times since April last year pledging peace and cooperation but little progress has been made to improve dialog and strengthen exchange and cooperation.

Moon said in a Liberation Day address on Thursday marking Korea's independence from Japan's 1910-45 colonial rule that it was to the credit of his policy of Korean national peace that dialog with the North was still possible.

"In spite of a series of worrying actions taken by North Korea recently, the momentum for dialog remains unshaken," Moon said.

The North's spokesman said it was "delusional" to think that inter-Korean dialog will resume once the military drills with the United States are over.

The spokesman left open the possibility of talks with the United States, speaking of upcoming dialog between the two countries but warned it will have no place for the South.

"South Korea is poking around hoping to reap the benefits of future dialog between the North and the United States but it will be a good idea to give up such foolishness," the unnamed spokesman said.

Trump and Kim have met twice since their first summit in Singapore last year and said their countries will continue talks, but little progress has been made on the North's stated commitment to denuclearise.