In the aftermath of Pyongyang conducting its fifth and largest nuclear test, world leaders have come together to condemn North Korea. The International Atomic Energy Agency, the nuclear watchdog of the United Nations, has also spoken out, branding North Korea's actions as a "clear violation of numerous UN Security Council resolutions" and a "complete disregard of the repeated demands of the international community".

United States

The US was quick to condemn the nuclear test and President Barack Obama has warned that provocative action by North Korea would have "serious consequences".

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He has also vowed to take all necessary action to protect South Korea from the North, including providing them with a nuclear umbrella.

President Obama has reportedly spoken to South Korean President Park Geun-hye over the phone in the aftermath of the nuclear test. The two leaders have agreed to use all available means to pressure North Korea into abandoning its nuclear programme, which is said to include the option of adopting a new UN Security Council resolution.

US Assistant Secretary of State Daniel Russel has said that it will be closely working with Japan, China, Russia and South Korea to continue placing pressure on the North Korean regime. His words came ahead of a meeting with Japan's Foreign Minister, Fumio Kishida.

According to Reuters, Russel said: "The fact is, there is an accelerated pattern of very serious provocation that violates international law and threatens regional stability."

South Korea

South Korea's Finance Minister, Yoo Il-ho, has said preparations must be made to respond to the increasing geopolitical tension, including the possibility of spikes in financial market volatility due to North Korea's nuclear test.

"We must prepare to respond to change in market conditions with greater alertness than ever before," Il-ho told Reuters.

Meanwhile, President Geun-hye has described the atomic test as an act of "fanatic recklessness".

China

While China's Foreign Ministry has said it "resolutely opposes" North Korea's nuclear test, its official Xinhua news agency has urged for restraint among the international community. Describing the test as "not wise", it also condemned the South's decision to deploy an advanced US anti-missile system in the region.

Foreign Ministry spokeswoman Hua Chunying said that China would be lodging a diplomatic protest with the North Korean embassy.

Japan

Japan's Defence Minister, Tomomi Inada, has expressed concern over the grave threat to Japan based on the North's nuclear test. He has also said that, based on the magnitude of the tremor caused by the test, Japan does not believe it was a test of a hydrogen device.

Inada said: "Considering that North Korea has developed missile technologies capable of delivering weapons of mass destruction, [the latest nuclear test] is a grave threat to the national security of Japan as well as the peace and security of north east Asia and the international community. We absolutely cannot accept it."

United Kingdom

Foreign Secretary Boris Johnson has described the nuclear test as "needless provocation".

Russia

Russia's Foreign Minister, Sergei Lavrov, held a joint press conference with US Secretary of State John Kerry, during which he said: "I'm very much concerned and the resolution of the Security Council must be implemented and we must send this message very strongly."