By Hyonhee Shin

SEOUL (Reuters) - North Korean leader Kim Jong Un has paid his respect at a family mausoleum to mark the birthday of his late father and former leader Kim Jong Il, state media KCNA said on Monday.

Kim Jong Il's birthday, which falls on Feb. 16, is widely celebrated as a major holiday in North Korea, called the Day of the Shining Star.

But it was the first time in four years that the young Kim visited the Kumsusan Palace of Sun in the capital Pyongyang, which houses the embalmed bodies of his father and grandfather, for the anniversary.

Accompanied by Kim Yo Jong, his sister and a senior ruling Workers' Party official, among other aides, Kim Jong Un paid homage "in the humblest reverence," KCNA said.

"He expressed his solemn will to devote himself to the sacred struggle for the eternal prosperity of the country, the security of the people and the promotion of their well-being," it said.

The Kim dynasty that has ruled North Korea since its founding after World War Two and has sought to strengthen their grip on power by building cults of personality around them, though Kim Jong Un has shown signs of increasingly trying to stand more on his own feet without relying on his predecessors.

In another dispatch, KCNA said Kim attended a groundbreaking ceremony on Sunday for the final phase of his pet project to build 50,000 new homes in Pyongyang.

The ambitious initiative was launched in 2021 as part of Kim's five-year plan to boost the economy, and designed to distribute at least 10,000 new apartments in Pyongyang each year, though some analysts have questioned its feasibility amid international sanctions and economic woes.

During the ceremony, Kim lauded construction workers and officials for achieving nearly 400% progress last year compared to 2020, and pledged another plan to continue expanding the city.

The project would "usher in a new era of prosperity of Pyongyang in which the ideal streets of the people to be proud of in the world are built every year," KCNA said.

(Reporting by Hyonhee Shin; Editing by Ed Davies and Michael Perry)