Japan's Shinzo Abe says will make firm response to North Korea's nuclear test

Japanese Prime Minister Shinzo Abe said on Wednesday the nation 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.

Abe, speaking to reporters, said Japan absolutely 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.