North Korea would bolster its defences against the United States and consider restarting "all temporarily suspended activities," state media KCNA reported Thursday, an apparent reference to a self-imposed moratorium on testing its nuclear bombs and long-range missiles.

Tension has been rising over a recent series of North Korea missile tests. A US push for fresh sanctions was followed by heated reaction from Pyongyang, raising the spectre of a return to the period of so-called "fire and fury" threats of 2017.

North Korean leader Kim Jong Un convened a meeting of...