North Korea fired a ballistic missile on Sunday in an apparent provocation to test the response from new US President Donald Trump, the South Korean defence ministry said.
The missile, launched around 7:55 am (2255 GMT Saturday) from Banghyon air base in the western province of North Pyongan Province, flew east towards the Sea of Japan (East Sea), it said.
It flew about 500 kilometres (310 miles) before falling into the sea, a defence ministry spokesman said, adding the exact type of missile had yet to be identified.
"It is believed that today's missile launch ... is aimed at drawing global attention to the North by boasting its nuclear and missile capabilities," the ministry said in a statement.
"It is also believed that it was an armed provocation to test the response from the new US administration under President Trump," it added.
An army official quoted by Yonhap news agency ruled out the possibility of a long-range missile test, describing the device as an upgraded version of the North's short-range Rodong missile.
"The launch also appears to be part of the North's effort to steadily improve its missile capabilities," the official was quoted as saying.
- 'Clear provocation' -
The launch came after after Trump assured visiting Japanese Prime Minister Shinzo Abe that Washington was committed to the security of its key Asian ally.
"We will work together to promote our shared interests, of which we have many, in the region, including freedom from navigation and defending against the North Korean missile and nuclear threat, both of which I consider a very, very high priority," Trump said Friday.
The two leaders did not immediately respond to Sunday's launch, which came after Pyongyang carried out two atomic tests and fired multiple missiles last year, triggering enhanced UN sanctions.
"We are aware of the reports and are closely monitoring the situation", a White House official told AFP, adding that the president had been briefed.
South Korea's acting president Hwang Gyo-Ahn vowed a "corresponding punishment" in response, while Japan's top government spokesman Yoshihide Suge called the launch "absolutely intolerable".
"Considering the missile was launched immediately after the Japan-US summit, it is clearly a provocation to Japan and the region," Suge told reporters.
The launch came on the heels of a visit to Seoul by new US Defense Secretary James Mattis last week, who had warned Pyongyang that any nuclear attack would be met with an "effective and overwhelming" response.
"Any attack on the United States or our allies will be defeated and any use of nuclear weapons would be met with a response that would be effective and overwhelming," Mattis said.
North Korea is barred under UN resolutions from any use of ballistic missile technology but six sets of UN sanctions since Pyongyang's first nuclear test in 2006 have failed to halt its drive for what it insists are defensive weapons.
Last year the country conducted numerous tests and launches in its quest to develop a nuclear weapons system capable of hitting the US mainland.
In January leader Kim Jong-Un boasted that Pyongyang was in the "final stages" of developing an intercontinental ballistic missile (ICBM) in an apparent attempt to pressure the incoming US president.
Trump shot back on Twitter, saying "It won't happen."
Washington has repeatedly vowed that it would never accept North Korea as a nuclear-armed nation and the latest launch poses a test for Trump, who will need the help of Beijing, Pyongyang's closest ally, to deal with the reclusive state.
- Nuclear push -
Analysts are divided over how close Pyongyang is to realising its full nuclear ambitions, especially as it has never successfully test-fired an ICBM.
But all agree it has made enormous strides in that direction since Kim took over after the death of his father and longtime ruler, Kim Jong-Il, in December 2011.
The young leader is planning a "prime time" nuclear weapons push this year to take advantage of a leadership transition in South Korea -- where the president has been impeached -- and the US, a high-ranking North Korean defector said recently.
Thae Yong-Ho, a former deputy ambassador to Britain who recently defected to Seoul, said Kim would never trade away the North's nuclear arsenal no matter how large a financial incentive might be offered.
Seoul, South Korea | AFP