Test confirms nuclear warhead can be mounted on rockets: North Korea

This confirmation comes a few hours after the fifth atomic explosion was conducted

North Korea said on Friday its latest nuclear test had confirmed that it could mount a nuclear warhead on a rocket, hours after it carried out a fifth atomic explosion.

"The nuclear test finally... Confirmed the structure and specific features... Of a nuclear warhead that has been standardised to be able to be mounted on strategic ballistic rockets," the state-run Korean Central News Agency said.

North Korea is believed to have conducted a fifth nuclear test, its most powerful to date, South Korea's military said after monitors detected a 5.3-magnitude "artificial earthquake" near its main nuclear site.

A confirmed test by the isolated North would send tensions soaring over its nuclear and ballistic missile ambitions, which have already earned international condemnation and United Nations sanctions.

The quake was detected near North Korea's Punggye-ri nuclear test site as the country celebrates Foundation Day, which marks the anniversary of the founding of the nation in 1948.

"We believe that it was a nuclear test. We are trying to figure out whether it was successful. The blast measured about 10 kilotons," a defence ministry spokesman told reporters.

The North's third nuclear test, staged in February 2013, was previously considered the most powerful to date, with a yield of six to nine kilotons.