North Korea launched at least two projectiles into the sea on Friday, South Korea's military said, shortly after Pyongyang described South Korea's president as "impudent" and vowed that inter-Korean talks are over.

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." It has also fired several short-range missiles in recent weeks.

South Korea's military said the North fired two more projectiles into the sea on Friday from an area on the country's eastern coast. South Korea's Joint Chiefs of Staff did not immediately say what the weapons were or how far they flew.

Japan's defence ministry said it did not see any imminent security threat from the latest projectile launch.

The loss of 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 spokesperson said in a statement.

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

'Nothing more to talk about'

"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 spokesperson for the committee for the peaceful reunification of the country said.

The committee is the North's government outfit tasked with managing the 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 North Korea's Central News Agency (KCNA).

A handout photo shows U.S. President Donald Trump and South Korean President Moon Jae-in at the Observation Post Ouellette at Camp Bonifas on June 30, in Panmunjom, South Korea. North Korea has criticized the South for taking part in military drills with the United States. (Handout/Dong-A Ilbo/Getty Images)

Moon and North Korean leader Kim Jong-un have met three times since April last year, pledging peace and co-operation. But little progress has been made to improve talks between them and strengthen co-operation.

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 dialogue with the North was still possible.

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

The North's spokesperson said it was "delusional" to think talks between the two Koreas will resume once the military drills with the United States are over.

The spokesperson left open the possibility of talks with the United States, speaking of upcoming dialogue 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 dialogue between the North and the United States but it will be a good idea to give up such foolishness," the unnamed spokesperson 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 on denuclearization.