Apart from overseeing missile launches and nuclear detonations, North Korean leader Kim Jong-un takes time out for less menacing activities, whether it is visiting corn fields or shoe factories in the country.

Now, in what is seen as a leadership outreach, Kim and his wife Ri Sol-ju conducted a trial run of a new trolleybus in the capital Pyongyang.

"The Supreme Leader went around the city aboard a trolleybus at midnight despite his busy time, saying that he would feel easy when he personally examines the test of new type trolleybus with which he acquainted himself during his recent visit to the remodelled Pyongyang Trolley Bus Factory," the Korean Central News Agency (KCNA) reports.

Kim felt "easy and proud" while going around in the trolleybus made by North Korean workers, the report said.

Kim "earnestly called on the sector of the passenger service in the capital to strive to satisfactorily provide traffic convenience for the citizens in the cold winter days in particular, always regarding the popular masses' demand and appreciation as absolute standard and with the revolutionary outlook on the masses strictly based on this and the spirit of devoted service to the people," the report added.

In a separate development, the North Korean foreign ministry denounced US President Donald Trump's recent State of the Union address. Calling it the "height of arrogance" and "arbitrariness", the foreign ministry spokesman said his country would be fully prepared to thwart Trump's "sinister" plans.

The spokesman said: "Trump described last year as a year fully recorded with incredible progress and extraordinary success. This is indeed the height of Trump-style arrogance, arbitrariness and self-conceit. The whole world is deeply concerned, seeing as an omen of new disaster the address of Trump who asserted 'America First' and 'unmatched power' based on nuclear weapons while forcing other countries to submit themselves to the US chauvinistic interest."