North Korea test-fired three ballistic missiles on Tuesday, in further defiance of the international community and in apparent reaction to the planned deployment of a U.S. defense system in the South.

The launches drew swift condemnation from the United States and Japan, who vowed a coordinated response to Pyongyang's repeated violations of UN sanctions that bar it from weapons tests.

North Korea threatened Monday to take "physical action" after Washington and Seoul announced they would deploy a sophisticated US anti-missile defence system to counter the growing menace from Pyongyang.

Seoul and Washington on Friday revealed their decision to deploy the Terminal High Altitude Area Defense (THAAD) system in the South following recent North Korean missile and nuclear tests.

North Korea hit back at the United States on Sunday for labeling it a money-laundering state, describing it as a "nonsensical" effort that only revealed the flaws of existing sanctions pushed by Washington.

The U.S. on Wednesday branded Pyongyang a "global money laundering concern", aiming to lock the impoverished by nuclear-armed country out of the world financial system.

The United States took steps Wednesday to further lock North Korea out of the world financial system as it officially labeled the country a "global money laundering concern."

The action would prevent both direct and indirect North Korean financial activities within the U.S. banking system, ensuring that any third-party deals involving significant sums of U.S. dollars or other currencies cannot transit the United States.

Donald Trump's push for the White House has caught the approving eye of North Korea, which appears to be relishing the potential strategic benefits of a Trump presidency.

An editorial Wednesday in the ruling party's official newspaper, the Rodong Sinmun, gleefully pointed to rival South Korea's "anxiety" at the prospect of the former TV reality star winning November's U.S. election.

South Korea's defense ministry said Monday it had detected signs that North Korea was preparing a ballistic missile launch, as Japan reportedly put its military on intercept alert.

U.N. resolutions ban North Korea from any use of ballistic missile technology, although it regularly fires short-range missiles into the sea off its east coast.

The European Union on Friday further tightened sanctions against North Korea over nuclear and ballistic missile tests carried out in defiance of U.N. Security Council resolutions.

The 28-nation bloc said it adopted new restrictions in the trade, financial, investment and transport sectors in order to complement U.N. resolutions against the Democratic People's Republic of Korea, the north's official name.

Visiting U.N. Secretary General Ban Ki-moon on Wednesday left open the possibility of running for the South Korean presidency after his term with the world body ends.

North Korea has challenged United Nations chief Ban Ki-moon to clarify the legal basis for U.N. sanctions against it, Pyongyang's state media said Tuesday.

The North's permanent representative to the U.N. wrote to Secretary-General Ban on Monday, saying that U.N. sanctions imposed over its nuclear tests and "peaceful satellite launches" had no legal foundation, KCNA news agency reported.

North Korea urged South Korea on Friday to accept leader Kim Jong-Un's proposal for military talks and to ease tensions that surged after the North's fourth nuclear test in January.

Kim had offered the military dialogue during a marathon speech to the recently concluded congress of North Korea's ruling Workers' Party -- the first event of its kind for more than 35 years.