North Korean leader Kim Jong-un called for a rapid expansion in the revolutionary movements of ideology, technology and culture throughout society, despite strains on the country's economy.

The North's state-run Korean Central News Agency(KCNA) said on Friday that Kim delivered the written message to the Fifth Conference of the Frontrunners of the Three Revolutions that opened in Pyongyang on Thursday.

In the message, Kim said the movements will spread throughout cities and counties, pledging to set up exhibition halls.

The leader expressed disappointment in the lack of progress, saying those putting in their utmost efforts are intimidated by economic difficulties and other challenges.

Kim highlighted self-reliance in urging officials to move forward, despite the vast tasks and challenges that face the nation .

The latest conference is being held for the second time under the current leader since November 2015. Prior sessions were held in 1986, 1995 and 2006.