North Korea today fired two projectiles into the sea between the Korean peninsula and Japan, officials said.
South Korea's joint chiefs of staff said the weapons were fired from a region near the North Korean capital of Pyongyang.
It has not been confirmed whether the weapons were ballistic missiles or rocket artillery, or how far they flew.
It follows a string of weapons tests apparently aimed at ramping up pressure on the United States over a stalemate in nuclear negotiations.
The North said on Sunday it was running out of patience with the US, warning a close personal relationship between leaders Kim Jong-un and Donald Trump wouldn't be enough to prevent nuclear diplomacy from derailing.
In a statement released by the state media, senior North Korean official Kim Yong Chol said the Trump administration would be "seriously mistaken" if it ignores an end-of-year deadline set by the North Korean leader for mutually acceptable terms.
Meanwhile, Nam Sung-wook, a North Korea expert at Seoul's Korea University, said the North is likely to ramp up its weapons demonstrations in coming weeks, which may include more powerful mid-range missiles to increase pressure on Washington ahead of Kim's deadline.
Additional reporting by agencies.
