North Korea nuclear test raises spectre of stronger ’rounds of action’

North Korea pounded its chest on Tuesday after conducting what is believed to have been a powerful, underground nuclear test, threatening stronger "rounds of action" against its enemies.

The test was immediately criticized by the international community including China, the hermit kingdom’s closes ally.

The nuclear explosion comes at a time of heightened tension with North Korea, which has recently issued threats against both its South Korean neighbour and the United States.

North Korean officials claim the test showed "as much self-restraint as possible" and threatened further action, raising the spectre of a possible strike on North America.

A North Korean state-run news agency confirmed the successful test about three hours after seismic activity suggested an underground explosion had occurred.

"It was confirmed that the nuclear test, that was carried out at a high level in a safe and perfect manner using a miniaturised and lighter nuclear device with greater explosive force than previously, did not pose any negative impact on the surrounding ecological environment," it said, according to the BBC.

[ Related: China joins U.S., Japan in condemning North Korea nuclear test ]

The North Atlantic Treaty Organization (NATO) joined a chorus of international outrage, condemning the nuclear test "in the strongest terms" as a flagrant violation of United Nations resolutions.

U.S. President Barack Obama called for a swift international response to the test, while the governments of Russia, South Korea, Japan and Britain all similarly called for North Korea to stand down.

The BBC reports that monitors in Vienna marked the underground explosion as stronger than the country's last test, in 2009, despite involving what is believed to have been a smaller device.

The test, North Korea's third, follows a successful missile launch in December.

It is feared that, if it develops a small enough nuclear device, North Korea could arm a missile and possibly launch a nuclear strike on the U.S.

A bizarre propaganda video was released by North Korea last week in which images of New York City being devastated were spliced with peaceful images of North Korea and the tune to "We Are The World."

[ Related: North Korea turns ‘We Are the World’ into propaganda video ]

There is really no way to know what is next, from a country that's entire foreign policy is threatening and antagonizing.

Here is NATO's statement in full:

We condemn in the strongest terms the test by North Korea of a nuclear weapon, conducted in flagrant violation of relevant United Nations Security Council resolutions.

This irresponsible act, along with the December missile launch, poses a grave threat to international and regional peace, security and stability. North Korea’s pursuit of weapons of mass destruction represents continued defiance of the UN Security Council and the broader international community.

We call on the North Korean authorities to cease immediately such provocative actions, to meet their obligations under international law and to comply fully with the decisions of the international community, as expressed by the United Nations Security Council.