North Korean leader Kim Jong-un said a "crucial case" has happened that could threaten the safety of his people and country in nationwide anti-epidemic efforts, state media reported Wednesday, spurring speculation that a coronavirus outbreak could have hit parts of the country.

Kim made the remarks as he presided over an extended politburo meeting of the ruling Workers' Party on Tuesday, accusing senior officials of neglecting their duties in carrying out measures needed to fight the global pandemic, according to the Korean Central News Agency.

"Senior officials in charge of important state affairs neglected the implementation of the important decisions of the party on taking organizational, institutional, material, scientific and technological measures ... associated with the worldwide health crisis, and thus caused a crucial case of creating a great crisis in ensuring the security of the state and safety of the people and entailed grave consequences," Kim was quoted as saying by the KCNA.

"He analyzed in the strong terms that a major factor braking and hindering the implementation of the important tasks discussed and decided at the party congress and plenary meetings of the party is the lack of ability and irresponsibility of cadres," the KCNA added.

The KCNA did not elaborate on what the "crucial case" was.

North Korea has claimed to be coronavirus-free but has enforced tight border controls and other antivirus measures since the beginning to ward off an outbreak on its soil.

The North has recently called for "maximum vigilance" against the coronavirus amid concerns over the global spread of the highly contagious Delta variant and pandemic fatigue.

Pointing out chronic inability and irresponsibly among cadres, Kim called for "a more fierce partywide campaign" against "ideological faults and all sorts of negative elements" being exposed among them.

At Tuesday's meeting, "an organizational issue" was also discussed, including the election of new politburo members and a secretary of the party's Central Committee, the KCNA said, without providing details on those newly elected.

Experts here are divided over what Kim's remarks mean, with some raising the possibility of an outbreak of the coronavirus in the North and others speculating that they were aimed at tightening discipline among his staff.

"A huge problem appears to have happened in its antivirus campaign in such cities as Sinuiju and Hyesan bordering China," said Cheong Seong-chang, director of the Center for North Korean Studies at the Sejong Institute.

The unification ministry in Seoul said it needs to monitor follow-up reports from Pyongyang to figure out what the crucial case might be but noted that the latest politburo meeting appears in part aimed at tightening internal discipline amid the country's protracted anti-pandemic campaign.

"There could be various possibilities, including tightening internal discipline," a ministry official told reporters on condition of anonymity. "It is still hard to say (what the crucial case might be) since details were not disclosed."

The official said that North Korea appears to be continuing to use politburo meetings to review the country's antivirus efforts. Last year, the North held 12 such sessions to deal with coronavirus-related situations.

Tuesday's politburo meeting came 11 days after North Korea held a four-day plenary meeting of the Workers' Party, the third of its kind this year. (Yonhap)