SEOUL - For the first time since leader Kim Jong Un took power in 2011, North Koreans were asked to take loyalty oaths on his birthday, said a South Korean research institute, amid other steps the country is taking to solidify his rule.

The loyalty oaths were administered on what is believed to have been Mr Kim’s 40th birthday on Jan 8, according to Seoul-based organisation South and North Development Institute (Sand), which released photos of the oath in an ornate folder on May 3.

North Korea has never officially confirmed Mr Kim’s birthdate, and traditionally, such oath ceremonies have been held on the anniversaries of the birthdays of his father and grandfather, who are the nuclear-armed country’s previous rulers.

“Kim Jong Un’s choice to host a loyalty oath ceremony on his 40th birthday, as he begins his 13th year in power, signals a shift towards political assertiveness, departing from his predecessors’ approach,” Sand said in an analysis.

Sand president Choi Kyong-hui told Reuters that North Korea could move to designate Mr Kim’s birthday as an official anniversary as soon as 2025.

The Kim family dynasty has ruled the country since its founding after World War II, strengthening its grip on power by building cults of personality around the members.

For the first time, in 2024, North Korea stopped referring to the April 15 birth anniversary of founding leader Kim Il Sung as the “Day of the Sun”, according to a Western tour agency that has partners in Pyongyang, and analysts who study state media.

“We should view this as part of North Korea’s effort to further bolster Kim Jong Un’s leadership propaganda campaign,” Ms Rachel Lee from the Washington-based 38 North programme said of the decision to drop “Day of the Sun”.

She noted that while such efforts are not new, they happen in phases over the years, with North Korea visibly accelerating efforts to play up Mr Kim’s leadership in certain years.

Mr Kim has also been showing off his daughter during official visits to everything, from factories to missile launches, in what analysts said is aimed at bolstering the family’s claim to power.

In April, Pyongyang released a new song featuring North Koreans of different backgrounds, ranging from children to troops and medical staff, exuberantly belting out lines such as “Let’s sing, Kim Jong Un the great leader” and “Let’s brag about Kim Jong Un, a friendly father”. REUTERS