North Korea successfully tested a new engine for an intercontinental ballistic missile (ICBM), state news agency KCNA said.

The successful ground jet test of a new type high-power engine of inter-continental ballistic rocket was conducted under the guidance of leader Kim Jong Un at Sohae Space Center in North Phyongan Province, the agency said.

The latest test takes place under the shadow of simmering tensions between North Korea and the west over the reclusive country's nuclear and ballistic missile programmes.

Kim Jong said test underscored North Korea's the ability to conduct a nuclear strike against the United States.

"Dear Comrade Kim Jong Un said now we can mount an ever more powerful nuclear warhead on a new intercontinental ballistic rocket and put the den of evil in the United States and all over the world within our strike range," KCNA said.

"Now the DPRK can tip new type inter-continental ballistic rockets with more powerful nuclear warheads and keep any cesspool of evils in the earth including the U.S. mainland within our striking range and reduce them to ashes."

The UN imposed this month the toughest ever sanctions on North Korea after the nuclear rogue regime conducted it fourth nuclear test in January, followed up with a string of suspected missile tests.

Kim said in March North Korea has miniaturized nuclear warheads that can be mounted on ballistic missiles, following up with a threat earlier that it will launch pre-emptive nuclear strikes on the US and North Korea.

Pyongyang had also ordered the military to be ready to use nuclear weapons any time, following the UN sanctions on the country for its pursuit of nuclear weapons and missile technology.

North Korea conducted its fourth nuclear test in January saying it successfully tested a hydrogen bomb.