North Korea has announced that it successfully tested an engine designed for an intercontinental ballistic missile.

According to the KCNA news agency, the new type of engine would “guarantee” the ability to launch a nuclear strike on the US mainland.

The test was conducted at North Korea’s long-range missile launch site near its west coast.

It is the latest in a series of tests and launches carried out by North Korea.

Kim Jong-un supervised the test, state media report, during which “the engine spewed out huge flames with a deafening boom”.

North Korea would now be able to “keep any cesspool of evils in the earth including the US mainland within our striking range,” the country’s leader was quoted as saying.

In response to the latest announcement, US State Department spokesman Mark Toner said North Korea should “refrain from actions and rhetoric that further destabilize the region and focus instead on taking concrete steps toward fulfilling its commitments and international obligations”.

In March, North Korea said it had developed nuclear warheads small enough to fit on ballistic missiles.

However, experts cast doubt on the claims.

Last month also saw North Korea threaten “indiscriminate” nuclear strikes on the US and South Korea as they held big joint military drills, which the north sees as a rehearsal for an eventual invasion.

Meanwhile, the US imposed new sanctions on North Korea following a nuclear test in January and a satellite launch in February, widely seen as a test of banned missile technology.