North Korea fired two ballistic missiles Thursday as it justified its recent blitz of sanctions-busting tests as necessary countermeasures against joint military drills by the United States and South Korea.
As the United Nations Security Council met to discuss Pyongyang's Tuesday launch of an intermediate-range ballistic missile over Japan, North Korea blamed Washington for "escalating the military tensions on the Korean peninsula".
The recent launches -- six in less than two weeks, including likely its longest-ever test by distance -- were "the just counteraction measures of the Korean People's Army on South Korea-US joint drills," Pyongyang's foreign ministry said.
Early on Thursday, South Korea's military said it had detected two short-range ballistic missiles launched from the Samsok area in Pyongyang towards the East Sea, also known as the Sea of Japan.
"Our military has reinforced monitoring and surveillance and is maintaining utmost readiness in coordination with the United States," Seoul's Joint Chiefs of Staff said in a statement.
Japan's coastguard also confirmed the launch of two potential ballistic missiles, with Prime Minister Fumio Kishida telling reporters that the recent testing spate was "unacceptable".
The first missile flew about 350 kilometres (217 miles) at a maximum altitude of around 100 kilometres, while the second missile had a flight range of about 800 kilometres at an altitude of around 50 kilometres, according to Japanese defence minister Yasukazu Hamada.
"Regardless of its aim, North Korea's repeated launches of ballistic missiles cannot be tolerated," Hamada told reporters
"We cannot overlook the significant improvement of its missile technology."
Pyongyang's Tuesday firing of what officials and analysts said was a Hwasong-12 that travelled likely the longest horizontal distance of any North Korean test, prompted the United States to call for the emergency Security Council meeting.
At the meeting, North Korea's longtime ally and economic benefactor Beijing also blamed Washington for provoking the spate of launches by Kim Jong Un's regime.
Deputy Chinese ambassador to the UN Geng Shuang said North Korea's recent launches were "closely related" to military exercises in the region conducted by the United States and its allies.
Geng accused the US of "poisoning the regional security environment".
Seoul, Tokyo and Washington have ramped up joint military drills in recent weeks, including large-scale naval manoeuvers and anti-submarine exercises.
The United States said Wednesday it would redeploy the nuclear-powered USS Ronald Reagan to the Korean Peninsula for a second visit in less than a month.
North Korea's foreign ministry accused the US of "posing a serious threat to the stability of the situation on the Korean peninsula" with the deployment of the aircraft carrier.
The spate of launches is part of a record year of weapons tests by isolated North Korea, which leader Kim Jong Un has declared an "irreversible" nuclear power, effectively ending the possibility of denuclearisation talks.
US ambassador to the UN Linda Thomas-Greenfield called for "strengthening" existing sanctions on North Korea, something China and Russia vetoed in May.
The council has been divided on responding to Pyongyang's nuclear ambitions for months, with Russia and China on the sympathetic side and the rest of the council pushing for punishment.
Analysts say that Pyongyang has seized the opportunity of stalemate at the UN to conduct ever more provocative weapons tests.
Officials in Seoul and Washington have been warning for months that Pyongyang will conduct another nuclear test, likely after the Chinese Party Congress on October 16.
"At this point, for Kim to turn back and halt provocations would seem counterproductive to his interests, not to mention the amount of resources squandered to conduct these weapons tests," Soo Kim, an analyst at the RAND Corporation, told AFP.
"We are indeed in a cycle of weapons provocations. What's left, essentially, is an ICBM test and potentially the long-awaited seventh nuclear test."