Russia has warned of tensions in North Korea slipping out of control, after Pyongyang announced it was placing its rockets on stand-by.
Russian Foreign Minister Sergei Lavrov warned the situation could slip “toward the spiral of a vicious circle”.
North Korean leader Kim Jong-un made the missile order after talks responding to US stealth bomber flights over the Korean peninsula, state news agency KCNA said.
The time had come to “settle accounts” with the US, KCNA quoted him as saying.
Annual military drills and fresh UN sanctions have angered North Korea.
After a late-night meeting with the army’s strategic rocket force, Kim Jong-un “judged the time has come to settle accounts with the US imperialists”, KCNA reported.
Kim Jong-un was said to have condemned US B-2 bomber sorties over South Korea as a “reckless phase” that represented an “ultimatum that they will ignite a nuclear war at any cost on the Korean Peninsula”.
US mainland and bases in Hawaii, Guam and South Korea were all named as potential targets.
The US – which flew two stealth bombers over the peninsula on Thursday as part of the ongoing annual US-South Korea military drills – has said it is ready for “any eventuality” on the peninsula.
Thousands of North Korean soldiers and students later took part in a mass rally in the centre of Pyongyang in support of Kim Jong-un’s announcement, beneath large portraits of his father Kim Jong-il and grandfather Kim Il-sung.
A South Korean defence ministry spokesman described the North Korean decision as a “continuing measure”, after its announcement to adopt “combat posture”.
China, North Korea’s biggest trading partner, immediately reiterated its call for all sides to ease tensions.
But Russian Foreign Minister Sergei Lavrov went further, voicing concern that “we may simply let the situation slip out of our control and it will slide into a spiral of a vicious circle”.
While condemning Pyongyang’s actions as “unacceptable”, Sergei Lavrov gave a more general warning that “unilateral steps being taken around North Korea that manifest themselves in a build-up of military activity”.
Sergei Lavrov added what was needed was not a build-up of military muscle and a pretext for using military means to achieve “geopolitical objectives”, in remarks seen as an implicit criticism of US bomber flights.