SEOUL, South Korea (AP) -- North Korea on Wednesday fired several unidentified projectiles off its east coast, South Korea's military said, less than a week after the North launched two short-range ballistic missiles into the sea.
Observers say the launches were aimed at ramping up pressure on the United States to make concessions as the two countries are struggling to resume diplomacy on the North's nuclear weapons program.
South Korea's Joint Chiefs of Staff said in a statement the latest launches were done from the North's northeastern area. It said South Korea's military is monitoring for possible additional launches by North Korea.
It wasn't immediately known exactly what North Korea fired or how far the projectiles flew.
The launches came six days after North Korea fired two short-range ballistic missiles that Seoul officials say flew 600 kilometers (370 miles) before landing off the North's east coast.
The latest launches also came hours after a senior U.S. official said President Donald Trump has sent mementos from his brief visit to North Korea last month to Kim.
The official said a top staffer from the National Security Council hand-delivered photographs from the June Trump-Kim meeting at the demilitarized zone to a North Korean official last week. The Trump administration official spoke on the condition of anonymity because the official wasn't authorized to speak publicly.
Diplomacy between North Korea and the United States remained deadlocked since the second Trump-Kim summit in Vietnam in February ended without any agreement. The summit fell apart after Trump rejected Kim's demand for widespread sanctions relief in return for dismantling his main nuclear complex, a partial disarmament step.
North Korea's state media said leader Kim Jong Un supervised a test of a new missile Thursday designed to deliver "solemn warning" to South Korea over its purchase of high-tech U.S.-made fighter jets and its plans to conduct military drills that Pyongyang sees as an invasion rehearsal.
South Korea's military said the flight data of the weapon launched Thursday showed similarities to the Russian-made Iskander, a short-range, nuclear-capable missile. A North Korean version could likely reach all of South Korea -- and the 28,500 U.S. forces stationed there -- and would be extremely hard to intercept.