A U.N. committee on Tuesday adopted the resolution urging the Security Council to refer the North's rights situation to the International Criminal Court. It's the first time a U.N. resolution included the idea that the North's absolute leader Kim Jong Un could be targeted by prosecutors. Before the U.N. vote, a North Korean envoy threatened a nuclear test.

On Thursday, Pyongyang's Foreign Ministry called the resolution's approval a "grave political provocation," saying it was orchestrated by the U.S. though it was drafted by the European Union and Japan.

An unidentified ministry spokesman told state media that the North's war deterrence will be strengthened in an "unlimited manner" to cope with U.S. hostility, which is "compelling us not to refrain from conducting a new nuclear test any longer." His comments on the nuclear test were near identical to what Choe Myong Nam, a foreign ministry adviser for U.N. and human rights issues, said at the U.N.

The North has used similar rhetoric previously when there has been increased tension with other countries.

Analysts say it's unlikely the North will follow through on its threats to conduct a nuclear test because that would invite further international condemnation and derail efforts to attract foreign investment and aid to revive its moribund economy.

China and Russia, which hold veto power on the Security Council, will not let the council refer the North's rights situation to the criminal court, but North Korea also knows the two countries do not want another nuclear test by Pyongyang, said Lim Eul Chul, a North Korea expert at South Korea's Kyungnam University. China and Russia voted against the non-binding resolution, which goes to the General Assembly for a vote in the coming weeks.

North Korea, however, often confounds outside analysts' predictions and doesn't always act according to a set pattern. Two deadly attacks blamed on Pyongyang that killed 50 South Koreans in 2010 were a surprise because they came amid relatively easing tensions with the U.S. and South Korea.

The U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies said Wednesday the North may be restarting a plant that can reprocess nuclear fuel into weapons-grade plutonium for the first time in six years. The finding is based on analysis of recent commercial satellite imagery at the North's main nuclear facility.

North Korea conducted an atomic bomb test in 2006, 2009 and 2013, each time inviting international sanctions. A fourth test would mark another defiant response to U.S.-led international pressure on North Korea to abandon its nuclear weapons program, because that could put the country a step closer to the goal of producing warheads small enough to mount on a missile capable of reaching the U.S.