North Korea promised on Sunday to carry out a "new form" of nuclear test after a recent round of ballistic testing, heightening tensions on the divided Korean Peninsula.
The North's Foreign Ministry didn't specify what it meant by a "new form" of nuclear testing. However, Western allies have long believed the isolated state is trying to make small nuclear weapons that can be carried by intercontinental ballistic missiles, the New York Times reports.
Pyongyang's new threat follows test-firings of two Rodong midrange ballistic missiles, which landed in the sea between North Korea and Japan on Wednesday.
North Korea prompted tightened sanctions and global condemnation when it carried out its third nuclear test a year ago.
“North Korea should bear in mind that if it ignores the stern demand from the neighboring countries and the international community and carries out a nuclear test, it will have to pay a price for it," South Korea Foreign Ministry spokesman Cho Tae-young said.
North Korea has struck a defiant tone despite overtures from South Korea that include generous foreign investment if the North ends its nuclear program. Pyongyang's warnings also come as North Korean and Japanese officials are meeting for their first high-level talks in more than a year.