Pyongyang launches ballistic missiles toward its eastern waters, as Washington redeploys nuclear-powered USS Ronald Reagan aircraft carrier near the Korean Peninsula.
North Korea has fired two short-range ballistic missiles toward its east coast in the direction of Japan, following joint South Korean and US missile drills and the return of a US aircraft carrier to the region.
The launch on Thursday was reported by South Korea's Joint Chiefs of Staff and the Japanese government.
Japan's Defence Minister Yasukazu Hamada said one of North Korea's missiles flew to an altitude of 100 kilometres with a range of 350 km and the second missile flew to an altitude of 50 kilometres with a range of 800 km.
Minister Hamada also noted that missiles likely flew in an irregular trajectory.
North Korea's Foreign Ministry said its recent blitz of missile launches were "counteraction measures" against joint military drills by the United States and South Korea.
The launch was the North's sixth round of weapons firings in less than two weeks, which has prompted condemnation from the United States and other countries.
The launch came two days after North Korea fired an intermediate-range missile over Japan for the first time in five years. Foreign experts said the missile fired on Tuesday involved an intermediate-range weapon capable of reaching the US Pacific territory of Guam and beyond.
"This is the sixth time in the short period just counting the ones from the end of September," Japanese Prime Minister Fumio Kishida told reporters. "This absolutely cannot be tolerated."
Tensions running high
The North's flurry of weapons tests in recent days came after the United States staged military drills with South Korea and Japan in the waters off the Korean Peninsula's east coast. North Korea views such drills as an invasion rehearsal.
After Tuesday's launch, the United States, Britain, France, Albania, Norway and Ireland called for an emergency meeting of the UN Security Council.
North Korea's Foreign Ministry said in a statement on Thursday that it strongly condemns "the Korean People's Army on South Korea-US joint drills escalating the military tensions on the Korean Peninsula."
North Korea carried out a record number of missile tests this year amid long-stalled diplomacy with the United States.
Observers say North Korea aims to expand its nuclear arsenal to boost its leverage in future negotiations with the United States.