Latest incident comes 3 days before inauguration of new South Korean president 

North Korea fired a suspected ballistic missile toward its eastern sea on Saturday, the South Korean and Japanese militaries said, in its second launch this week, apparently continuing a provocative streak in weapons demonstrations that may culminate with a nuclear test in the coming weeks or months.

South Korea's Joint Chiefs of Staff didn't immediately say what kind of weapon the North fired or how far it flew. Japan's Defence Ministry said the launch was possibly ballistic, but didn't immediately provide the flight details.

The launch came three days after South Korea and Japan's militaries detected the North firing a suspected ballistic missile from near its capital, Pyongyang, on Wednesday, and three days before the inauguration of South Korean President-elect Yoon Suk-yeol, who has vowed to take a tougher approach over the North's nuclear ambitions.

The latest launch was likely North Korea's 15th round of missile firings this year, including its first test of an intercontinental ballistic missile since 2017 that demonstrated potential range to reach the entirety of the U.S. mainland.

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Experts say the unusually fast pace in testing activity underscores a brinkmanship aimed at forcing the United States to accept the idea of the North as a nuclear power and remove crippling sanctions. There are also signs that North Korea is restoring tunnels at a nuclear testing ground, where it had conducted its sixth and last nuclear test in September 2017, in possible preparations for another explosive test.

North Korean leader Kim Jong-un has punctuated his missile tests with statements warning that the North could proactively use its nuclear weapons if threatened or provoked, which experts say possibly portends an escalatory nuclear doctrine that would create greater concerns for South Korea and Japan.

The South Korean and Japanese militaries said the North Korean missile fired on Wednesday travelled about 500 kilometres at a maximum altitude of 800 kilometres. North Korean state media has yet to comment on that test.