North Korea marked the anniversary of the birth of its founder Kim Il Sung Thursday, with mask-wearing citizens placing flowers before his statue in Pyongyang.

The grandfather of the current leader Kim Jong Un was born 109 years ago and April 15 is the most important date in the nuclear-armed state's annual political calendar, where it is known as the Day of the Sun.

But the country is more isolated than ever after it imposed a strict border lockdown to protect itself from the coronavirus pandemic that first emerged in neighbouring China.

It still insists that it has not had any cases of the disease -- a claim that analysts doubt -- but has paid a heavy economic price.

Current leader Kim Jong Un's grandfather was born 109 years ago and April 15 is the most important date in the state's annual political calendar
Current leader Kim Jong Un's grandfather was born 109 years ago and April 15 is the most important date in the state's annual political calendar AFP / KIM Won Jin

Groups of Pyongyang residents went to Mansu hill, where giant bronze statues of founder Kim and his son and successor Kim Jong Il gaze out over the capital, to lay flowers at their base.

"Comrades Kim Il Sung and Kim Jong Il will always be with us" read a floral frieze.

Citizens, many of the women in traditional dress, were assembled in key locations for performances to mark the occasion. In the streets, everyone wore masks, although the dancers for the shows had their faces uncovered.

It represented an increase in festivities compared with last year's subdued events.

North Korea is more isolated than ever after it imposed a strict border lockdown to protect itself from the coronavirus pandemic
North Korea is more isolated than ever after it imposed a strict border lockdown to protect itself from the coronavirus pandemic AFP / KIM Won Jin

"North Korea has brought the commemorations back to almost normal compared to last year when most activities were cancelled due to Covid," Yang Moo-jin of the University of North Korean Studies in Seoul told AFP.

Nonetheless several usual elements were missing, notably the Pyongyang Marathon, the country's biggest annual tourism money-spinner, which was again cancelled due to the pandemic.

Pyongyang has also announced it will not attend the Tokyo Olympics.

Leader Kim was absent from the commemorations last year, raising eyebrows at the start of an extended period out of public view that triggered feverish speculation over his health.

But, unlike in 2020, a floral basket stood in pride of place in front of the statues, the usual location for his tribute.

Earlier this week he posed for pictures with delegates to a ruling party conference.

At a five-yearly party congress in January he repeatedly apologised for mistakes in economic management, saying the last five years had been the "worst" time.

North Koreans are taught from birth to revere Kim Il Sung and Kim Jong Il, and all adults wear badges depicting one or both men.

Kim Il Sung died in 1994 but remains the country's Eternal President, and his preserved body lies in state in a red-lit chamber at the Kumsusan Palace of the Sun on the outskirts of the capital.