Hundreds of thousands of North Koreans rallied Friday in the freezing cold to celebrate the country's rocket launch, staging a choreographed show of defiance under their youthful leader's "endless" wisdom.

The enormous rally in central Pyongyang, shown on state television, came two days after the launch of the three-stage rocket and just ahead of the anniversary Monday of the death of new leader Kim Jong-un's father.

The West fears the launch has taken the nuclear-armed state a step closer to firing intercontinental ballistic missiles across the planet, and it has provoked U.N. Security Council condemnation along with calls for more sanctions.

Refueling its criticism of Wednesday's launch, the U.S. State Department said Kim had the chance as new leader "to take his country back into the 21st century" but instead was making the "wrong choices".

Unbowed, North Korean state media said Kim, who is in his late 20s, had personally signed off on the rocket launch and had declared his regime's "unshakable stand" that the program will continue.

Kim stressed the need "to launch satellites in the future... to develop the country's science, technology and economy", according to the North's official Korean Central News Agency (KCNA) as it gave new details of the launch.

The "dear respected Marshal" visited mission control an hour before the rocket took off on Wednesday morning and praised the "ardent loyalty and patriotic devotion" of the technical team, KCNA said in the report early Friday.

The report gave no reaction to the international opprobrium that has been heaped on North Korea since the rocket went up, ostensibly to place a research satellite in orbit, with even close ally China expressing its "regrets".

But Friday's rally was an emphatic demonstration of organized support for the Kim dynasty, as the massed ranks of civilians and soldiers chanted their obeisance under giant portraits of Kim's father and grandfather.

Many of the civilians were in dark winter coats, and the soldiers in olive-green overcoats and Russian-style trappers' hats, as they pumped their fists and chanted "long live!", the state TV's hour-long broadcast showed.

Addressing the crowd, which stood in organized ranks in Kim Il-Sung Square, senior officials lavished praise on the Kim dynasty and its scion for the rocket launch -- which came after an April attempt ended in fiery failure.

"This was achieved thanks to the Great Marshal Kim Jong-un's endless loyalty, bravery and wisdom," said Jang Chol, president of the State Academy of Sciences, which helps to steer North Korea's rocket program.

The U.N. Security Council held emergency talks on Wednesday after the North, already under international sanctions for nuclear tests in 2006 and 2009, ignored pleas from friends and foes to stop the launch.

The council warned of possible measures over what the United States called a "highly provocative" act as countries including South Korea and Japan pressed for stronger sanctions against Pyongyang.

Both South Korea and Japan are holding general elections in the coming days, shadowed by the perennial unpredictability of their deeply poor but heavily armed neighbor.

China -- North Korea's leading patron -- supported the UN statement but its foreign ministry also pushed back against the pressure for stronger action, arguing that any response by the international community should be "prudent".

Analysts say the symbolism of the launch was a prime motivating factor for North Korea as Kim shores up his leadership credentials.

"The launch means the fulfillment of Kim Jong-Il's last wish," said Yoo Ho-yeol, a political science professor at Korea University in Seoul.

"As such, it helps cement Jong-un's grip on power and strengthens his authority over the North's military elites, securing their loyalty and a sense of solidarity under his leadership," Yoo said.

While there is no hint of another nuclear test being imminent in North Korea, the U.S. and South Korean intelligence communities will be looking for any insights into the country's level of ballistic expertise.

South Korea's navy has recovered a section of the rocket that splashed into the sea, apparently a fuel tank inscribed with the name of the "Unha-3" rocket, the defense ministry in Seoul said.

"This debris is expected to be an important piece of information in determining North Korea's rocket capability," ministry spokesman Kim Min-seok said. (AFP)