In a series of posting on his Twitter feed, the Foreign Secretary said Britain was working with the United States and allies in the region to find a diplomatic solution to the stand-off between Pyongyang and Washington.
Johnson’s intervention came as Chinese President Xi Jinping appealed to both sides for calm amid fears the worsening war of words between North Korea and the US could lead to a military conflict with catastrophic consequences for the region, the Press Association reported.
In a telephone conversation with Donald Trump, he urged both sides to avoid words or actions that could worsen the situation.
The Americans have been pressing China to pressure North Korea into abandoning its nuclear programme amid fears that it is close to developing a missile which could hit the US mainland.
State-run China Central Television quoted Xi as telling the president that the “relevant parties must maintain restraint and avoid words and deeds that would exacerbate the tension on the Korean Peninsula”.
The call followed the latest barrage of threats from Trump, declaring the US military forces were “locked and loaded” and warning Kim he “will regret it fast” if he takes any action against US territories or allies.
The crisis blew up following the disclosure that US intelligence analysts had concluded North Korean scientists had developed a nuclear warhead small enough to fit on a ballistic missile.
It prompted Trump to warn that he would unleash “fire and fury” on North Korea if it did not stop its threats to the US.
Pyongyang responded by announcing plans for a series of missile test firings towards the US Pacific island territory of Guam – the home to two major US military bases.
Despite the increasingly bellicose statements, Trump’s comments did not appear to be backed by significant military mobilisation on either side of the Pacific, while a discreet diplomatic back channel with the regime is reported to remain open.
As a precaution, Japan has deployed missile defence batteries under the path a North Korean missile might take. However life on the streets of the North Korean capital, Pyongyang, is reported to remain calm.