North Korea said Wednesday it had successfully tested a hydrogen bomb, leading to condemnation from around the world, but also widespread scepticism that the claim is true.
Q: What is the difference between this and previous tests?
A: North Korea says that the latest test was of a thermonuclear bomb, also known as a hydrogen bomb. These bombs are potentially many times more powerful than previous atomic weapons it has tested, and a successful test would mark a step up in North Korea's nuclear capabilities.
Q: Can we be sure that Pyongyang's claims are true?
A: There has been no independent verification of North Korea's claim to have detonated a hydrogen bomb, and this could take days or even weeks.
An initial US analysis, based on seismic analysis and data from regional partners, showed that the activity was "not consistent with North Korean claims of a successful hydrogen bomb test," the White House said. An international nuclear test watchdog said the shock from the test was of the same size as a previous one in 2013, while a South Korean military official said the blast was too weak to be from a hydrogen bomb.
Q: What are the possible implications within North Korea?
A: Leader Kim Jong Un "might very much need this to stabilize his power," according to Yu Yingli, an Asia expert at the Shanghai Institute for International Studies.
Kim came to power after his father died in late 2011, and has since undertaken what is widely regarded as a purge of some top officials in an effort to cement his status.
Q: What are the possible implications for North Korea internationally?
A: While North Korea's relations with South Korea and the United States could hardly be worse, this test - whether a hydrogen bomb or a less powerful device - is bound to damage ties with its main ally China as well as with Russia, according to Yu.
As after previous nuclear tests, the United Nations is likely to impose further international sanctions, backed by China, Yu said. The UN Security Council pledged Wednesday to take "significant measures" against North Korea.
Kim "wants to force talks with the United States on an equal footing," said German lawmaker and Korea expert Hartmut Koschyk. "He seems to have overestimated his position."