SEOUL-- North Korea fired two unidentified projectiles into the sea off its eastern coast on Saturday, South Korea's military said.
The latest launch comes shortly after U.S. President Donald Trump said he had received a "very beautiful letter" from North Korean leader Kim Jong Un.
North Korea has fired a series of missiles and rockets since Kim and Trump agreed at a June 30 meeting to revive stalled denuclearisation talks.
A U.S. official said that at least one projectile was launched and that it appeared to be similar to previous short-range missiles fired by Pyongyang.
Trump played down the recent North Korean weapons launches when he spoke to reporters earlier on Friday, saying: "I say it again: There have been no nuclear tests. The missile tests have all been short-range. No ballistic missile tests. No long-range missiles."
Trump also said Kim had written in his letter that he was "not happy" about the U.S.-South Korean war games and missile tests. Kim has said the weapons tests were a response to U.S.-South Korean military drills being held this month. He added he could have another meeting with Kim.
The United States and South Korea have kicked off their largely computer-simulated exercises as an alternative to previous large-scale annual drills that were halted to expedite denuclearisation talks.
North Korea decries such exercises as a rehearsal for war aimed at toppling its leadership.
The projectiles were fired at dawn on Saturday from the area around the northeastern city of Hamhung, South Korea's Joint Chiefs of Staff said in a statement.
Large solid-fuel rocket engines for North Korea's ballistic missile program are most likely being produced at a factory complex in Hamhung, monitoring group 38 North said last year. Hamhung also has a testing site for those engines.
Kim Dong-yup, a former naval officer who teaches at Seoul's Kyungnam University said the weapons tested on Saturday could be related to the completion of North Korea's new rocket artillery system that required multiple launches of the same kind.