North Korean leader Kim Jong-un has warned against factionalism in the nation's ruling party, its official media said Wednesday, as part of ongoing efforts to reinforce ideology education after the stunning execution of his uncle for treason charges.

"(We) failed to learn and root out the emergence of a modern-time faction within the party in advance" despite diverse efforts to set the monolithic control system, Kim was quoted as saying by the North's Korea Central News Agency.

He made the remarks in his speech during the closing ceremony of the 8th Conference of the Ideological Officials of the Workers' Party of (North) Korea on Tuesday.

His comment on factional activity is seen as referring to the case of Jang Song-thaek, the leader's uncle and No. 2 man who was executed in December for treason charges.

"All efforts of the party's ideological projects should be poured into the firm establishment of the monolithic control system ... and to eradicate factionalism," he said.

Stressing that such sectarianism is caused by changes in ideology, the young leader of the communist country called for "proactive operations to prevent the toxin of capitalism from encroaching on us and to nullify their imperialistic ideological movements."

The two-day conference in Pyongyang was held for the first time in 10 years. The communist country has stressed unity surrounding its leader Kim and striven to reinforce ideology education on its people particularly after Jang's execution. (Yonhap)