SEOUL, South Korea (AP) — The latest on North Korea's announcement that is has conducted a hydrogen bomb test (all times local):
Russia's Foreign Ministry says it hasn't been confirmed that North Korea has carried out an actual nuclear test.
In a statement, the ministry calls on "all interested sides to preserve maximum restraint and to not take actions that could rouse the uncontrolled growth of tensions in Northeast Asia."
— Jim Heintz, Moscow
The EU foreign policy chief says that North Korea's nuclear test, if confirmed, would represent "a grave violation of the DPRK's international obligations not to produce or test nuclear weapons."
Federica Mogherini said in a statement that these obligations are determined by U.N. Security Council resolutions. The North's action would represent "a threat to the peace and security of the entire Northeast Asia region."
She called on North Korea to re-engage in a credible and meaningful dialogue with the international community, in particular in the framework of the six-nation talks, "and to cease this illegal and dangerous behavior."
She says she will consult with South Korean and Japanese foreign ministers and work with the U.N. Security Council meeting in an emergency session later Wednesday.
— Raf Casert, Brussels
The head of the International Atomic Energy Agency says if confirmed, North Korea's hydrogen bomb test would be in in clear violation of U.N. Security Council resolutions and "is deeply regrettable."
IAEA Director General Yukiya Amano issued a statement which urged North Korea to implement fully all relevant resolutions of the U.N. Security Council and the IAEA.
Amano said that IAEA remains ready to contribute to the peaceful resolution of the nuclear issue by resuming its nuclear verification activities in the North once a political agreement is reached among countries concerned.
— George Jahn, Vienna
Britain's foreign secretary says that if a nuclear bomb has been detonated by North Korea, it would be a grave breach of U.N. Security Council resolutions.
Philip Hammond condemned North Korea's announcement of the nuclear test, and said it underlined the "very real threat that North Korea represents to regional and international security."
Hammond, who is visiting China, said in a statement that he discussed the matter with his Chinese counterpart, Yang Jiechi. He says they "have agreed to work with other members of the U.N. Security Council towards a robust international response."
Hammond said he would also speak Wednesday with his Japanese and South Korean counterparts.
A South Korean lawmaker says the country's spy agency told him in a private briefing that Pyongyang may not have conducted a hydrogen bomb test given the relatively small size of the seismic wave reported.
Lawmaker Lee Cheol Woo says the National Intelligence Service told him that an estimated explosive yield of six kilotons and a quake with a magnitude of 4.8 were detected Wednesday.
According to him, that's smaller than the estimated explosive yield of 7.9 kilotons and a quake with a magnitude of 4.9 that were reported after the 2013 nuclear test, and only a fraction of a typical successful hydrogen bomb test's explosive yield of hundreds of kilotons.
Lee says the agency told him that even a failed hydrogen bomb detonation typically yields tens of kilotons. Lee sits on the parliament's intelligence committee.
China, Australia and France have strongly condemned North Korea's announcement of a nuclear test.
China, the North's closest ally, says the reported test was carried out in defiance of the international community and urged North Korea to refrain from acts that might worsen tensions on the Korean Peninsula.
Australian Foreign Minister Julie Bishop says in a statement Wednesday that the action "confirms North Korea's status as a rogue state and a continuing threat to international peace and security."
French President Francois Hollande said in a statement that "France condemns this unacceptable violation of Security Council resolutions and calls for a strong reaction from the international community."
South Korea's President Park Geun-hye has convened an emergency national security council meeting and is vowing a tough response to the North's bomb test.
Park said at the start of the meeting that the government "must get North Korea to face corresponding measures based on closed cooperation with the international community."
She says: "It's not only grave provocation of our national security, but also an act that threatens our lives and future. It's also a direct challenge to world peace and stability."
Park also ordered the military to bolster its combined defense posture with the U.S. military, saying South Korea will sternly deal with any additional provocation by North Korea.
She called for a swift, accurate analysis on the North's claim to have conducted a hydrogen bomb test.
— Hyung-jin Kim, Seoul, South Korea
In Pyongyang, North Koreans reacted enthusiastically to the news that the country has carried out its fourth nuclear test since 2006.
Kim Sok Chol, a 32-year-old man who watched the TV announcement on a big screen at the train station square, told The Associated Press that he does not know much about what a hydrogen bomb is, but added that "since we have it, the U.S. will not attack us. I think the first successful H-bomb test is a great national event."
Ri Sol Yong, a 22-year-old university student, said the test "gives us more national pride."
She said, "Thanks to the fact that our country is a nuclear weapons state, I can study at the university without any worries. If we didn't have powerful nuclear weapons, we would already have been turned into the slaves of the U.S."
The White House says it can't confirm a North Korean nuclear test, but said it would condemn such a test as a violation of U.N. Security Council resolutions.
North Korea said Wednesday it has conducted a hydrogen bomb test — a move that would put the country a step closer toward improving its still-limited nuclear arsenal.
National Security Council spokesman Ned Price says the U.S. is "aware of seismic activity on the Korean Peninsula in the vicinity of a known North Korean nuclear test site and have seen Pyongyang's claims of a nuclear test."
He calls on North Korea to abide by its international obligations and commitments and said the U.S. consistently made clear that it will not accept North Korea as a nuclear state and will continue to defend U.S. allies in the region.
Crowds dressed in thick winter coats have gathered outside a large video screen near a Pyongyang train station to cheer and take video and photos on their mobile phones of the state TV anchor announcing the country had carried out a nuclear test.
Some people raised their hands and applauded. Many smiled and cheered.
South Korea says it will consult with allies and regional powers to get North Korea to face the consequences of the nuclear test it said it had carried out, such as additional U.N. sanctions.
Presidential security official Cho Tae-yong says: "We strongly condemn" the North's fourth bomb test.
He says North Korea must abide by U.N. resolutions that require the country to scrap its nuclear and ballistic missile programs completely and irreversibly.
South Korea's Defense Ministry also says it is bolstering security and monitoring on North Korea.
— Hyung-jin Kim, Seoul, South Korea
The head of the U.N. Comprehensive Test Ban Treaty Organization, which monitors worldwide for nuclear testing, says if confirmed, a nuclear test by North Korea would be a breach of the treaty and a grave threat to international peace and security.
Lassina Zerbo says in a statement that the universally accepted norm against nuclear testing has been respected by 183 countries since 1996.
Zerbo urged North Korea to refrain from further nuclear testing and join the 183 states who have signed the treaty.
— George Jahn, Vienna
Japanese Prime Minister Shinzo Abe says the North Korean announcement of a hydrogen bomb test is a threat to his nation's safety.
Abe told reporters: "We absolutely cannot allow this, and condemn it strongly."
He called it a violation of the U.N. Security Council agreements that is against the global efforts toward nuclear disarmament.
Abe says he will take "strong action," work with other nations, the U.S., South Korea, China and Russia, as well as through the U.N.
— Yuri Kageyama, Tokyo
The U.N. organization monitoring the world for signs of nuclear testing says it has detected "an unusual event in the Korean Peninsula."
The head of the Comprehensive Test Ban Treaty Organization Lassina Zerbo says in a statement: "Our International Monitoring System detected an unusual seismic event in the Korean Peninsula at latitude 41.27 longitude 129.10."
The location on the map places the epicenter at North Korea's Pyunggye-ri testing site in its northeastern mountains, where all of its nuclear tests have been conducted.
North Korea said Wednesday it had conducted a hydrogen bomb test, which, if confirmed, would put Pyongyang a big step closer toward improving its still-limited nuclear arsenal.
— George Jahn, Vienna