Kim sent a letter to ruling Workers’ Party officials attending a workshop on Monday that aimed to boost motivation for socialism and advance innovation in the party’s ideological work, KCNA said.

In the dispatch, Kim said the party has been “advancing in the face of the worst difficulties” and stressed the need to spread its vision for “juche”, or self-reliance.

“We should regard the ideological and moral strength of the popular masses as the foremost weapon as ever and stir it up in every way,” he said, according to KCNA.

The juche theory means that “nothing (is) impossible to do when the people are motivated ideologically”, he said.

North Korea faces mounting economic woes amid sanctions over its weapons programmes, natural disasters and Covid-19 lockdowns that sharply cut trade with China, its major ally and economic lifeline.

The US is pushing for tightening international sanctions over Pyongyang’s first full test of an intercontinental ballistic missile last week, despite opposition from China and Russia.

North Korea has not confirmed any Covid-19 cases, but closed borders and imposed strict travel bans and other restrictions.

Kim said the ideological campaign should focus on dispelling “evil spirits of anti-socialism” and non-socialist elements that have “gnawed away at our revolutionary position”, KCNA said.

Pyongyang has cracked down on the influx of South Korean music and entertainment via the Chinese border to curb what it says are non-socialist and anti-socialist influences.

Kim also called for beefing up visual content and stressed film as “an ideological education means of the greatest influence”.