North Korea has today fired at least one unidentified projectile from the country's western area, South Korea's military said, the second such launch in the last five days and a possible warning that nuclear disarmament talks could be in danger.
The South's Joint Chiefs of Staff had no other immediate details, and it wasn't clear what the North had fired.
But some analysts have said that if the North returns to the kind of longer-range banned weapons that it tested in 2017, when many feared a Washington-Pyongyang standoff could end in war, it will be a strong sign that a frustrated North Korea is turning away from diplomacy.
A summit earlier this year between American President Donald Trump and North Korean leader Kim Jong Un ended in failure.
North Korea wants widespread sanctions relief in return for disarmament steps that the United States has apparently seen as insufficient.
Longer-range ballistic missile tests, banned by the United Nations and seen as threatening by surrounding countries, would likely result in more sanctions.
The launch came hours after the North through its state media described its earlier firing of rocket artillery and an apparent short-range ballistic missile on Saturday as a regular and defensive military exercise and ridiculed South Korea for criticising the launches.
North Korea's official Korean Central News Agency published a statement by an unnamed military spokesman who called South Korea's criticism a "cock-and-bull story," hours before senior defence officials from South Korea, United States and Japan met in Seoul to discuss the North Korean launches and other security issues. Details from the meeting weren't immediately announced.
A separate statement by a North Korean foreign ministry spokesman, also unnamed, described the weekend launches as a "routine and self-defensive military drill."
It said Pyongyang has been demonstrating "maximum patience" over the impasse in nuclear talks with Washington and that "baseless allegations" against the North's legitimate exercise of sovereignty and self-defense rights would threaten to push things toward a direction "neither we nor they want to see at all."
South Korea's presidential Blue House and Defense Ministry have raised concern that Saturday's launches went against the spirit of an inter-Korean military agreement reached last year to cease all hostile activities and urged North Korea to refrain from acts that could escalate tensions.
North Korean state media on Sunday showed leader Kim Jong Un observing live-fire drills of long-range multiple rocket launchers and what appeared to be a new short-range ballistic missile fired from a launch vehicle.
South Korea's Joint Chiefs of Staff a day earlier said it detected North Korea firing multiple projectiles toward the sea from near the eastern town of Wonsan.
The launches, which likely represented North Korea's first ballistic missile test in more than 500 days, were clearly a sign of Pyongyang's frustration at stalled diplomatic talks with Washington meant to provide coveted sanctions relief in return for nuclear disarmament.
Following the collapse of his summit with President Donald Trump in February, Kim said he was open to a third meeting with Trump, but only if Washington offers mutually acceptable terms for an agreement by the end of the year.
Saturday's drills also highlighted the fragility of the detente between the Koreas, which in a military agreement reached last September vowed to completely cease "all hostile acts" against each other in land, air and sea.