NORTH KOREA: The UK and America today condemned a nuclear test carried out by North Korea.

Foreign Secretary William Hague called it a "violation of United Nations Security Council resolutions", while American President Barack Obama called it a "highly provocative act" that threatens US security and international peace.

The United States Geological Survey said it had detected a 4.9 magnitude earthquake in North Korea. The underground nuclear test defied UN orders to stop building atomic weapons.

It was North Korea's first since leader Kim Jong Un took power in December 2011.

Experts say regular tests are needed to perfect North Korea's goal of building nuclear warheads small enough to be placed on long-range missiles.

This atomic test – North Korea's third since 2006 – is expected to take the country closer to possessing nuclear-tipped missiles designed to strike America.

Mr Hague said: "North Korea's development of its nuclear and ballistic missile capabilities poses a threat to international and regional security.

"Its repeated provocations only serve to increase regional tension and hinder the prospects for lasting peace on the Korean Peninsula.

"The UK will begin urgent consultations with security council partners calling for a robust response."

UN secretary general Ban Ki-Moon said the test was "a clear and grave violation" of UN Security Council resolutions.

The Council will hold an emergency meeting in New York tonight.

Mr Obama promised to "continue to take steps necessary to defend ourselves and our allies."