U.S. President Barack Obama says North Korea’s reported nuclear test is a matter of grave concern to all nations.

Obama said in a statement released Monday, shortly after the North’s test, that North Korea’s attempts to develop nuclear weapons constitute a threat to international peace and security.

He noted that Pyongyang was directly and recklessly challenging the international community by defying the U.N. Security Council.

Obama said North Korea’s actions increase tensions and undermine stability in Northeast Asia, stressing that the North will not find international acceptance unless it abandons its weapons of mass destruction.