North Korea fired two more ballistic missiles off its east coast on Monday, as the powerful sister of leader Kim Jong Un warned US forces to halt military drills, saying the reclusive nuclear state could turn the Pacific into a "firing range".
The launches come just two days after North Korea fired an intercontinental ballistic missile (ICBM) into the sea off Japan's west coast, prompting the United States to hold joint air exercises with South Korea and separately with Japan on Sunday.
North Korea's state media confirmed it fired two projectiles from a multiple rocket launcher, aiming at targets 395 km (245 miles) and 337 km (209 miles) away, respectively.
"The 600mm multiple rocket launcher mobilised in the firing... is a means of tactical nuclear weapon," capable of "paralysing" an enemy airfield, state news agency KCNA said.
Japan's Defense Ministry said the two missiles, fired around 2200 GMT, reached a maximum altitude of about 100 km and 50 km, and fell outside Japan's EEZ.
Japanese Prime Minister Fumio Kishida said he had requested an emergency UN Security Council meeting over the launches, and Jiji news agency said the gathering was set for 2000 GMT Monday.
South Korea's Joint Chiefs of Staff strongly condemned the launches as a "grave provocation" that should be ceased immediately.
Seoul's foreign ministry announced sanctions on four individuals and five entities linked to Pyongyang's weapons programmes on Monday over the latest ICBM and missile tests, in what it called its fastest-ever such response to the North's provocations.
"Our government has made it clear that North Korea's provocations will definitely come at a price. Its repeated provocations will result in strengthening South Korea-US deterrence and tightening the global sanctions network," the ministry said in a statement.
The US Indo-Pacific Command said the latest launch did not pose an immediate threat but highlights the "destabilising impact" of North Korea's unlawful weapons programmes.
UN spokesman Stephane Dujarric urged Pyongyang to "immediately desist from taking any further provocative actions" banned under Security Council resolutions, and resume denuclearisation dialogue.
North Korean leader Kim's sister, Kim Yo Jong, warned against increased presence of US strategic military assets following the joint air drills with its Asian allies over the weekend.
"The frequency of using the Pacific as our firing range depends upon the US forces' action character," she said in a statement carried by KCNA.
The United States and South Korea are set to hold simulated nuclear tabletop exercises aimed at improving operations of American nuclear assets this week, as well as annual springtime Freedom Shield field training in March.
"Tension on the peninsula is likely to reach its peak in coming months as North Korea is accelerating its military actions with higher frequency, and her statement indicates that it would continue impromptu missile tests using the Pacific as its shooting range," said Yang Moo-jin, a professor at the University of North Korean Studies in Seoul.
Park Won-gon, a professor at Ewha Womans University in Seoul, said Monday's missile launch and statement are in line with the North Korean foreign ministry's recent threat to take "unprecedentedly persistent, strong" responses to the allies' joint military drills.
"North Korea seems to be trying to reinforce its nuclear capability by raising issue over the drills," Park said.
Monday's missile launch is the North's third known weapons test this year after it fired an unprecedented number of missiles last year, including ICBMs capable of striking anywhere in the United States.
Kim Yo Jong also criticised some South Korean experts' assessment that the "sudden" ICBM test required nine hours of preparations, saying the launch time was finalised after US and South Korean scout planes involved in air patrols went away.
"We have possessed satisfactory technology and capability and, now will focus on increasing the quantity of their force," she said. "We affirm once again that there is no change in our will to make the worst maniacs escalating the tensions pay the price for their action."