U.S. President Donald Trump said Saturday that North Korean leader Kim Jong Un expressed his desire in a letter to hold more summit talks as soon as U.S.-South Korea joint military exercises are over.

Trump wrote in his Twitter post that Kim also offered "a small apology for testing short-range missiles," without elaborating. The letter said missile testing "would stop when the (U.S.-South Korea) exercises end," Trump wrote.

"I look forward to seeing Kim Jong Un in the not too distant future! A nuclear free North Korea will lead to one of the most successful countries in the world!" Trump said.

Trump did not say when the letter was received.

His comments follow North Korea's firing of two projectiles toward the Sea of Japan early Saturday, the fifth round of launches by Pyongyang in just over two weeks.

The U.S. president said last Friday he had received a "beautiful" three-page letter from the North Korean leader in which Kim said he did not like conducting the short-range ballistic missile tests but justified the move as a response to the U.S.-South Korea drills.

The two leaders have held three face-to-face talks, the most recent in June at the Demilitarized Zone dividing the two Koreas. They agreed to restart denuclearization talks and invited each other to visit their capital cities.