North Korea has said it will never give up its nuclear weapons as long as the United States and its allies continue their 'blackmail and war drills' on its doorstep.

The North's official Korean Central News Agency reiterated the stance on Saturday as it reviewed the country's major nuclear weapons and missile tests this year.

North Korea carried out its most powerful nuclear test to date in September and launched three intercontinental ballistic missiles into the sea in July and November, indicating that it is closer than ever to gaining a nuclear arsenal which could viably target the mainland United States.

North Korea has claimed it will never give up its nuclear weapons while the United States and its allies continue to conduct military drills on its doorstep

Kim Jong-un ordered a missile test in response to military drills held between the United States and South Korea, which Washington describe as being 'defensive in nature'

The aggressive tests, which numbered 16 in 2017, have led to more international sanctions and pressure on North Korea amid concerns that the window for stopping or rolling back its nuclear programme is closing rapidly.

The US and South Korea have maintained that they will not negotiate with the North unless it is willing to discuss curbing its nuclear weapons and missile programme.

In its report on Saturday, KCNA said North Korea had taken steps for 'bolstering the capabilities for self-defence and pre-emptive attacks with nuclear force' in the face of a continued 'nuclear threat and blackmail and war drills' by the United States and its 'vassal forces'.

The North often lashes out at the annual military drills between the United States and South Korea, which the allies describe as defensive in nature.

North Korea has managed to extend the range of its missiles in a series of tests

North Korea has also managed to detonate its largest nuclear device in September

KCNA accused US President Donald Trump of employing unprecedented hostile policies against North Korea and threatening it with talks of pre-emptive strikes. It described North Korea as an 'undeniable new strategic state and nuclear power'.

'Do not expect any change in its policy. Its entity as an invincible power can neither be undermined nor be stamped out,' KCNA said.

'The DPRK, as a responsible nuclear weapons state, will lead the trend of history to the only road of independence,' it added, referring to North Korea by its official name, the Democratic People's Republic of Korea.