North Korea fired three ballistic missiles which flew about 1,000km and landed in waters within Japan's exclusive economic zone west of Hokkaido yesterday, just as G-20 leaders wrapped up a summit in the eastern Chinese city of Hangzhou.
The move also came just hours after Chinese President Xi Jinping, in a meeting with South Korean President Park Geun Hye in Hangzhou, made it clear that Beijing opposed Seoul's plan to deploy the United States' Terminal High Altitude Area Defence (Thaad) anti-missile system to protect the country against growing threats from the North.
"Mishandling the issue is not conducive to strategic stability in the region, and could intensify conflicts," Xinhua news agency quoted Mr Xi as saying.
He reaffirmed that China was committed to safeguarding peace and stability in the Korean Peninsula and pushing for denuclearisation, but said this should be achieved through dialogue, including resuming the stalled six-party talks involving China, the US, Russia, Japan and the two Koreas.
North Korea has now launched more than 30 ballistic missiles since its leader, Mr Kim Jong Un, assumed power in 2011.
Yesterday's provocation came barely two weeks after Pyongyang fired a submarine-launched missile about 500km towards Japan, displaying its improved missile capabilities.
The launching of the trio of Rodong mid-range missiles yesterday from Hwangju county in North Korea's east coast around noon local time (11am Singapore time) drew condemnation from the US and its allies, South Korea and Japan. A US official condemned the move as "reckless", while South Korea's Foreign Ministry described it as a "grave provocation" and "flagrant violation" of United Nations Security Council resolutions.
Japanese Prime Minister Shinzo Abe, who was in Hangzhou, said the "unprecedented" missile launches were a serious threat to security while Foreign Minister Fumio Kishida disclosed that Tokyo had lodged a stern protest through diplomatic channels in Beijing, and that there were plans to seek an emergency meeting of the UN Security Council.
Japan's Defence Minister Tomomi Inada noted that North Korea has fired 21 missiles since the beginning of the year.
"The way the missiles have been launched and their movement, as well as the capability of launching missiles from submarines, certainly show an improvement in their missile capabilities," she said, adding that Japan will make efforts to recover debris from the missiles for analysis.
Analysts could only speculate on the reasons for Pyongyang's latest missile launch, which range from a show of military strength to a protest against a new South Korean Bill against human rights abuses in North Korea.
"North Korea is trying to win some kind of political victory over the international community by flexing its missile power," said Dr Lee Sang Soo from Korea National Defence University's Research Institute for National Security Affairs.