In this photo provided by the North Korean government, North Korean leader Kim Jong-un, center, waves to participants as they gather for a group photo, in a celebration of the nation's 73rd anniversary at Kim Il Sung Square in Pyongyang, North Korea, Sept. 9. AP-Yonhap

North Korean leader Kim Jong-un visited a mausoleum of his late grandfather and national founder Kim Il-sung, and late father and former leader Kim Jong-il to mark the 73rd anniversary of the country's founding, state media reported Friday.

Kim and his wife, Ri Sol-ju, paid tribute at the Kumsusan Palace of the Sun, where the bodies of the late leaders lie in state, the Korean Central News Agency said.

"At the halls where the President and the Chairman lie in state, the General Secretary and his wife extended the best wishes of immortality to the great leaders who built the genuine people's country, the prosperous socialist country, and bequeathed it down to the future generations by dedicating all their lives," the KCNA said.

Ri's public appearance is believed to be the first in nearly four months since she attended a performance of the art groups of servicemen's families from large combined units of the Korean People's Army in May.

Kim's trip to the mausoleum comes after the North held a scaled-down military parade at midnight featuring artillery-carrying tractors rather than intercontinental ballistic missiles (ICBMs) and other strategic weapons.

Kim Yo-jong, the powerful sister of leader Kim, was also spotted paying tribute at the Kumsusan Palace in the fifth row, according to video footage released by the state-run Korean Central Television later in the day.

However, she did not appear in any photos or video clips of Thursday's military parade.

It is unusual for her to skip the North's military parade, as she has attended all parades on major anniversaries since 2015. At a military parade in celebration of the eighth congress of the North's ruling Workers' Party in January this year, she was spotted dressed in a long black leather coat similar to that of leader Kim's.

South Korea's unification ministry said it will keep an eye on Kim Yo-jong's status at the upcoming political events, such as the Supreme People's Assembly meeting later this month.

Accompanying Kim on the visit to the Kumsusan were top officials, including Choe Ryong-hae, president of the Presidium of the Supreme People's Assembly, and Jo Yong-won, secretary for organizational affairs of the party's Central Committee.

North Korea's military chief, Pak Jong-chon, who was recently elected a member of the Presidium of the ruling Workers' Party, also paid tribute.

The KCNA said Kim held a photo session with the participants of the parade and expressed appreciation for fully demonstrating the "fighting efficiency and unity of paramilitary and public security forces of our state."

He also voiced his expectation the participants would "fulfill their honorable mission and duty of defending the country and building socialism, while holding a rifle in one hand and a hammer, a sickle or a writing brush in the other hand."

Several celebratory events took place across the country to mark the founding anniversary, including dancing parties for the youth and members of the women's union, in an apparent effort to drum up domestic support amid a worsening economy from the prolonged COVID-19 pandemic and international sanctions. (Yonhap)