North Korea has conducted a nuclear test, according to local news reports. The state-KCNA agency reported the trial was more powerful than the previous test in 2006 and was "aimed at strengthening its self-defence nuclear deterrent in every way". The move has deepened international concern over the country's weapons programmes, with US officials confirming that it is consulting members of the UN Security Council on "next steps". In a separate statement, President Barack Obama said: "These actions, while not a surprise given its statements and actions to date, are a matter of grave concern to all nations. "North Korea's attempts to develop nuclear weapons, as well as its ballistic missile program, constitute a threat to international peace and security." In 2007, North Korea agreed to abandon all its nuclear programmes in six-party talks with South Korea, China, Japan, Russia and the US. It promised to shutdown the Yongbyon nuclear plant as part of an aid-for-disarmament deal and in response, the US removed North Korea from its terrorism blacklist. But the US suspended energy aid in December 2008 following a breakdown in international talks and Pyongyang's failure to verify the shutdown of its facility. In April, North Korea launched a rocket over northern Japan, which was widely considered to be a test of long-range missile technology. This prompted Tokyo to extend additional economic sanctions on the communist state and to deploy missile interceptors to the area. In the wake of last month's rocket launch, Japan had called for a fresh resolution by the UN Security Council to declare Pyongyang in violation of a previous resolution banning the firing of of ballistic missiles.