North Korean leader Kim Jong-un solemnly reopened the sprawling, granite mausoleum where his father's body lies in state as the nation marked the first anniversary of Kim Jong-il's death with sadness as well as celebration over last week's successful rocket launch.

Kim Jong-un joined top Workers' Party, military and government officials in a brief ceremony on Monday at the renovated Kumsusan mausoleum in Pyongyang's outskirts after being closed to the public since Kim Jong-il's death. The hall bearing Kim Jong-il's body was expected to open to guests in the afternoon.

At noon, North Koreans across the country stopped in their tracks to pay tribute to Kim, who died of a heart attack last year after 17 years in power. On one street in Pyongyang, construction workers took off their yellow hard hats and bowed at the waist as sirens wailed across the city for three minutes.

Unlike the dramatic shows of tears and mourning last year, the mood in Pyongyang was decidedly upbeat Monday, less than a week after North Korea successfully sent a satellite named after Kim Jongl into space.

Violation of UN resolutions

The controversial launch, widely condemned by the U.S. and other nations that consider it a violation of UN bans against missile activity, underlined Kim Jong-un's determination to continue carrying out his father's hardline policies even if they draw sanctions and international condemnation.

The West sees the rocket as a thinly disguised way of carrying out UN-banned tests of long-range missile technology, which it says not only threatens regional stability but is also a waste of resources when the country is struggling with a chronic food shortage.

Outsiders worry that in upcoming weeks Pyongyang will press ahead with a nuclear test, necessary in the march toward building a warhead small enough to be carried by a long-range missile.

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Military officers bow at an image of late North Korean leader Kim Jong-il during a meeting of top party and military officials in Pyongyang, North Korea, on Sunday. (Ng Han Guan/Associated Press)

At the mausoleum, renamed the Kumsusan Palace of the Sun, Choe Ryong-hae, the military's top political officer, said North Korea should be proud of the satellite. He called it a show of strength to the world.

Following tradition, North Korea reopened the mausoleum on the first anniversary of the leader's death and was expected to present Kim's body lying in state later Monday. Kumsusan, the palace where his father, Kim Il-sung, served as president, was reopened as a mausoleum on the first anniversary of his death in 1994.

Lined with snow-tinged firs, the plaza has been turned into a park at Kim Jong-un's orders and his father's portrait installed on the façade alongside that of Kim Il-sung.

At a memorial service on Sunday, North Korea's top leadership eulogized Kim Jong-il and praised his son, who gained national prestige and clout by going ahead with the rocket launch.

Kim Yong Nam, president of the Presidium of North Korea's parliament, credited Kim Jong-il with building Pyongyang's nuclear weapons program, and called the satellite launch a "shining victory" and an emblem of the promise that lies ahead with his son in power.

Kim Jong-un's gift to his father

Wednesday's launch was North Korea's second attempt in eight months to fulfil Kim Jong-il's 14-year quest to put a satellite into space. International experts confirmed that a satellite succeeded in reaching space.

The launch fit neatly into the preparations to mark the first anniversary of Kim's death and the rise of his young son.

Even before his death, Kim Jong-il had laid the ground for his son to inherit a government with national policies focused on science, technology and improving the economy. The son has been characterized as forward-thinking and tech-savvy — and the kind of man bold enough to take a gamble on a tricky rocket launch.

A launch in April, sent amid festivities to mark the centenary of the birth of North Korea founder Kim Il-sung, ended in failure shortly after liftoff.

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North Korean women lay flowers on Mansu Hill, in Pyongyang to show their respect to the late North Korean leaders Kim Il-sung and Kim Jong-il. (Jon Chol Jin/Associated Press)

Kim Jong-un made clear his intention to treat Wednesday's successful launch as a gift to his father, inviting scientists in charge of the launch from a west coast launch pad to Pyongyang for the mourning rites, according to state media.

On Sunday, a solemn Kim Jong-un joined the memorial service at the Pyongyang Indoor Stadium on the eve of the anniversary of Kim Jong-il's death.

Kim, whose entrances and exits usually are accompanied by a triumphant welcome song and a swell of cheers, entered the stage in silence, followed by top Workers' Party, government and Korean People's Army officials, as well as his aunt and uncle.

Tight security surrounded the gymnasium near Pyongyang's Pothong Gate. Armed soldiers in helmets posted along the street outside diverted traffic and pedestrians while more guarded every entrance to the building. The handful of foreign journalists allowed to cover the event were searched by armed soldiers.

In his speech, North Korea’s head of parliament Kim Yong-nam called Kim Jong-il a "peerless patriot" who strengthened the military and stood up to the United States.

As the hour-long ceremony came to a close, the band briefly played the mournful refrain to The General Will Always be With Us. After the musicians put down their instruments, Kim Jong-un stood up and led a silent procession out.