US President Barack Obama on Tuesday condemned North Korea's nuclear test as a "highly provocative act" that "undermines regional stability."
The isolated regime's nuclear weapons and missile programmes were in violation of international agreements, and "constitute a threat to US national security and to international peace and security," he said, dpa reported.
British Foreign Secretary William Hague condemned the test in similar terms, saying North Korea "has a choice to make."
"It can either engage constructively with the international community, cease developing its nuclear and ballistic missile programmes and return to negotiations, or face increasing isolation and further action by the [UN] Security Council and the international community."