North Korea fired two projectiles towards its eastern sea on Thursday as nuclear talks between Pyongyang and Washington remain at a deadlock.
The projectiles flew about 370 km at an altitude of some 90 km.
North Korea has also accused the United States and South Korea of continuing hostile policies, including joint military drills.
"Our military is tracking and monitoring relevant movements and maintaining readiness posture in case of additional launches", it said.
The reclusive North has long wanted to resume the lucrative visits, but they would now violate worldwide sanctions imposed on Pyongyang over its nuclear and ballistic weapons programmes.
Nam Sung-wook, a North Korea expert at Seoul's Korea University, said Pyongyang is likely to ramp up weapons demonstrations in coming weeks, which may include more powerful mid-range missiles to increase pressure on Washington ahead of Mr Kim's deadline.
The North then walked away from working-level nuclear talks with the USA in Sweden, saying it was disappointed at the lack of "new and creative" solutions offered by Washington. North Korea has hit out at South Korea and the USA for staging joint military drills that it sees as preparation for an invasion.
Japan's defence ministry said the objects launched from North Korea "appeared to be ballistic missiles".
The launches occurred on the day that South Korean President Moon Jae-in attended the funeral of his mother, who died on Tuesday.
At that meeting, Trump became the first sitting U.S. President to step over the border into North Korean territory.
During the previous 10 rounds of tests, the North test-fired short-range projectiles, including its version of Russia's Iskander ballistic missile and a "super-large" multiple rocket launcher system.
He described South Korean-built facilities there as "a hotchpotch with no national character at all" and "like makeshift tents in a disaster-stricken area or isolation wards", ordering their removal, Pyongyang's official KCNA news agency reported last week.
The meeting had been meant to build on their high-profile first summit in Singapore previous year, when Kim signed a vague pledge to work towards "denuclearization of the Korean Peninsula".
The missile test may have been partly aimed at underlining the point.
Contact between the North and South have stalled since Hanoi and Pyongyang has repeatedly excoriated Seoul for joint military drills with Washington and not following through on inter-Korean agreements signed past year. The country said it tested a new type of submarine-launched ballistic missile on October 2.
"It is consistent with hardening signals from state media since the breakdown of the Stockholm talks and Kim's climb up Mount Paektu", said Rachel Minyoung Lee, a senior analyst at NK News, a Seoul-based website specializing in North Korea news and analysis.