North Korean leader Kim Jong-un / Yonhap

By Park Ji-won

North Korean leader Kim Jong-un is believed to be turning 35 as of Tuesday, but there are no signs of celebration for the day, unlike the birthdays of his late father and grandfather.

The Ministry of Unification said the ministry didn't find any signs that they'd be holding ceremonial events for the day.

"In the North's New Year's calendar, there are no signs of commemorating the day or Jan. 8," unification ministry spokesman Baik Tae-hyun said during a regular briefing, Tuesday. "We will keep an eye on the related issues."

On Monday, the eve of his birthday, North Korean state media outlets didn't mention anything about his birthday. The North's 2019 calendar also marked the date as an ordinary working day.

The moves were likely in order to detract from his young age as a leader compared to his predecessors as ageism plays a big role in leadership in the North, critics say.

The country celebrates the birthdays of Kim's late grandfather and father, Kim Il-sung and Kim Jong-il as key national holidays to idolize the country's leaders.

Kim's father's birthday, Feb. 16 was designated as a national holiday in 1982 when he was 40 while Kim's grandfather's birthday, April 15 was designated as a national holiday in 1974.

Kim is known to have been born on Jan. 8, 1984, according to the unification ministry's directory. The book also states that there is speculation that his birth year might be 1982 or 1983. However, it is unknown when he was born as the North's government hasn't officially confirmed the date.

On Jan. 9, 2014, state media outlets reported one day later that former basketball star Dennis Rodman visited the North on Jan. 8 upon the birthday of Kim Jong-un. It was the first confirmation of his birthday since his inauguration in 2012.