Moon said, "The power lies within the people, and the government will work hard to make sure that the authorities will neither monitor nor suppress people's thoughts and will."

At the ceremony that took place at Seoul Plaza, he put forward "economic democracy" as a new challenge for the government.

"Extreme income and wealth inequality are threatening our democracy," he said, adding that the lack of job opportunities is the root of the problem.

"Job opportunities are not only an issue of our economy but also that of democracy."

Since solving the issue can't be done by the government alone, the country should reach an agreement on a new standard for economic democracy, he said.

"Taking this opportunity to honor the 30th anniversary of the pro-democracy uprising in June, I reassure you that our future lies in a social consensus on how we make concessions for others, share the burden together and narrow the level of inequality," the president said.

Acknowledging the difficulty of the challenge, he called on every party of the society to actively participate in the discussion to cope with it.

Moon became the first incumbent president to attend the ceremony since late Roh Moo-hyun did in 2007.

"For the past 30 years, all the developments and progress that our society has achieved are based on the pro-democracy uprising...And the Moon Jae-in government was able to take power against the backdrop of such achievements by the people," Moon said.

The president gave the people credit for the country'sflourishing democracy, by citing every historic grassroots democratic movement, including the recent monthlong peaceful protests to oust former President Park Geun-hye.

As one of the protesters who participated in the June 10 movement, Moon said he learned democracy becomes the strongest when its spirit is passed down to next generations "like running water." (Yonhap)