Barack Obama talks with Japan's Shinzo Abe about North Korean nuclear test: White House

President Barack Obama talked by phone on Wednesday with Japanese Prime Minister Shinzo Abe about the international response to North Korea's nuclear test, the White House said.

Obama reaffirmed the US commitment to Japan's security and the two leaders "agreed to work together to forge a united and strong international response to North Korea's latest reckless behaviour," the White House said in a statement.

"Separately, the President congratulated Prime Minister Abe on the recent agreement between Japan and the ROK (South Korea) to resolve the longstanding 'comfort women' issue," the statement said. 

In an earlier report, Abe said Japan would make a firm response to North Korea's challenge against nuclear non-proliferation, calling its latest nuclear test a threat to Japan's security. Adding, his country could not tolerate North Korea's nuclear testing.

North Korea said it had successfully conducted a test of a miniaturised hydrogen nuclear device on Wednesday morning. The announcement followed after South Korean officials detected an "artificial earthquake" near North Korea's main nuclear testing site. The test has likely become the country’s fourth known nuclear test.

According to an AP report, North Korea conducted its third nuclear test in February 2013. A confirmed test would mark another big step toward Pyongyang's goal of building a warhead small enough to be mounted on a missile capable of reaching mainland America's shores.

Meanwhile, US presidential candidates and members of the US Congress demanded more sanctions on North Korea, after its latest nuclear test, but major powers will likely be reluctant to take the tough steps necessary to force Pyongyang to abandon its weapons program, former US officials and analysts said.