North Korea has warned that nuclear war could break out any moment

US surveillance planes are also on the scene

Ambassador, Kim In-ryong, was speaking to the UN General Assembly committee on Monday and stated that North Korea is the only country that has been subjected to an extreme and direct nuclear threat from the U.S. in over four decades.

North Korea has warned that a nuclear war may break out at any time as the situation on the Korean peninsula has reached the "touch-and-go point".

North Korea had recently called on its citizens to be ready for a nation-wide struggle against "war thirsty" US President Donald Trump and his "gangster-like moves for domination and aggression".

"Cooperation between Japan and the United States, and that between Japan, the United States and South Korea, are more important than before to put diplomatic pressure (on the Democratic People's Republic of Korea) to the maximum level", Sugiyama was quoted as telling a press briefing after the talks.

Tensions over North Korea's weapons programme have soared in recent months, with Pyongyang launching a flurry of missiles and conducting its sixth and most powerful nuclear test. "History shows proof that we should protect ourselves on our own and our nuclear programs - are the programs of nuclear deterrence aimed at the protection of our independence", An Tong Chun, the first deputy speaker of the country's Parliament, said Sunday.

"The entire USA mainland is within our firing range and if the US dares to invade our sacred territory even an inch it will not escape our severe punishment in any part of the globe", the statement read.

The United States and South Korea on Monday began a 10-day joint naval exercise in a fresh show of force against the North, with a U.S. aircraft carrier and two USA destroyers taking part.

"Our country is being threatened, the very existence of the DPRK is at stake", he said, referring to statements by President Donald Trump at the UN General Assembly.

All the U.S. mainland is within firing of the DPRK.

The UN Security Council has unanimously ratcheted up sanctions on North Korea over its nuclear and ballistic missile programs since 2006.

Tension between the USA and North Korea have escalated in recent months with Kim ramping up the country's nuclear armament, touting its intercontinental ballistic missiles could strike the U.S.