North Korea’s leader Kim Jong Un has promised to “exponentially” boost the nation’s nuclear arsenal in a bid to defend the country against “hostile” forces.

Kim said the isolated state faces “a grave threat” due to “the reckless expansion” of a United States-led regional military bloc that is now developing into a nuclear-based threat, the official Korean Central News Agency reported on Tuesday.

In a speech marking the 76th founding anniversary of his government the previous day, Kim said this development is pushing North Korea to expand its military capabilities.

The Asian country will “redouble its measures and efforts to make all the armed forces of the state, including the nuclear force, fully ready for combat,” he promised.

The speech comes after Pyongyang disclosed a new platform likely designed to fire more powerful intercontinental ballistic missiles.

It has also resumed its practice of launching rubbish-carrying balloons towards South Korea in recent days.

North Korea has protested the July signing of a new US-South Korean defence guideline meant to integrate US nuclear weapons and South Korean conventional weapons to cope with growing North Korean nuclear threats.

North Korea said the guideline revealed its adversaries’ plots to invade. US and South Korean officials have repeatedly said they don’t intend to attack the country.

Since 2022, North Korea has significantly accelerated its weapons testing activities, and threatened it has the capability to launch strikes against the US and South Korea.

According to the Stockholm International Peace Research Institute (SIPRI), North Korea currently possesses about 50 nuclear warheads, though the exact number is unknown.

North Korea is subject to international sanctions because of its nuclear weapons and missile programmes. The last known nuclear test took place in 2017.

The US and South Korea have responded by expanding military drills that North Korea calls invasion rehearsals.