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In an image taken from footage shown by North Korea's KCTV and released by South Korea's Yonhap news agency on December 9, 2013, Jang Song-Thaek is reportedly being dragged away from his chair by two police officials during a meeting in Pyongyang. North Korea confirmed on December 9 that the powerful uncle of Kim Jong-Un, the nation's leader, had been removed. New reports from North Korea say that Jang has been executed.

Japanese lawmaker Antonio Inoki, left, Jang Song Thaek and Kenshiro Matsunami, a former Japanese lawmaker, hold a meeting in Pyongyang, North Korea, on November 6. Jang Song Thaek was regarded as the second most powerful figure in North Korea.

Kim Jong Un, left, and Jang Song Thaek walk through a cemetery for Korean War veterans on July 25 in Pyongyang, North Korea, marking the 60th anniversary of the signing of the armistice that ended hostilities on the Korean peninsula.

Chinese President Hu Jintao, right, greets Jang in Beijing on August 17, 2012. Jang met China's President and Premier in an effort to improve the relations between the two countries after Kim Jong Un irked Beijing with a rocket launch soon after taking power.

Kim Jong Un walks past his uncle after reviewing a parade of thousands of soldiers commemorating the 70th birthday of the late Kim Jong Il in Pyongyang on February 16, 2012.

Jang attends a meeting on developing the economic zones in North Korea, in Beijing, on August 14, 2012.

Jang follows Kim Jong Un during the funeral procession for Kim Jong Il in Pyongyang on December 28, 2011.

Jang is seen with Kim Jong Il, right, and Naguib Sawiris, center, the executive chairman of Cairo-based Orascom Telecom, at an undisclosed place in North Korea on January 23, 2011.

Jang, far right, appeared with Kim Jong Il and other officials during an inspection of the Mt. Ryongak Recreation Ground in Pyongyang, in an image released on January 18, 2009, by the official Korean Central News Agency.

(CNN) -- North Korean leader Kim Jong Un on Wednesday praised the recent purge of his uncle and former protector, saying it brought greater unity within the secretive, nuclear-armed state.

"In the seething period of the effort for building a thriving country last year, we took the resolute measure of removing the factionalists lurking in the Party," Kim said in a New Year's address, referring to the North's ruling Workers' Party of Korea.

"As our Party detected and purged the anti-Party, counterrevolutionary factionalists at an opportune time and with a correct decision, the Party and revolutionary ranks were further consolidated and our single-hearted unity was solidified to the maximum," Kim said, according to the text of the speech carried by North Korean state media.

Was uncle executed over business trade?

The purged uncle, Jang Song Thaek, was considered instrumental in Kim's rise to power in December 2011 and, until recently, was regarded as the second-most powerful figure in North Korea. But the young leader turned his back on Jang in spectacular fashion late last year, having him executed last month on charges he tried to overthrow the government.

A publicized purge

The death of Jang, who was married to Kim's paternal aunt, was announced in an unusually public declaration by the reclusive regime. Purges and executions of senior officials are believed to have taken place under the North's previous leaders, Kim's father and grandfather, but without such public fanfare.

North Korean state media attacked Jang's character and detailed an extensive list of his alleged crimes, describing him as "despicable human scum."

Kim's speech Wednesday is the first time he has publicly commented on the purge.

A range of different theories have been put forward for the real causes behind Jang's downfall. Last week, South Korea's main intelligence agency told lawmakers that it believed business disputes inside the North Korean regime had precipitated the purge.

Nuclear warning

In his speech, Kim also addressed his country's strained relationship with South Korea and the United States, warning that if war were to break out in the region, it would spiral into a nuclear confrontation.

"The U.S. and South Korean war maniacs have deployed legions of equipment for a nuclear war in and around the Korean Peninsula and are going frantic in their military exercises for a nuclear war against the North," Kim said. "This precipitates a critical situation where any accidental military skirmish may lead to an all-out war."

"Should another war break out on this land," he said, "it will result in a deadly nuclear catastrophe and the United States will never be safe."

But his words stopped well short of the alarmingly threatening language that peppered North Korean statements in early 2013 as tensions spiked over the regime's nuclear test in February and the resulting U.N. sanctions.

North and South

Kim called for better ties between the two Koreas, which have reestablished dialogue and reopened their shared industrial complex since the rocky period in the spring.

"A favorable climate should be established for improved relations between the North and the South," he said.

In South Korea, President Park Geun-hye said that her government would strive to maintain "impregnable" security and prepare for any possible provocations by the North.

Analysts have said that the purge of Jang could be a sign of instability inside North Korea and that Kim could seek to focus attention away from domestic issues by carrying out a provocative act, like another new rocket or nuclear test.

Park said the South Korean government would "redouble its efforts to further promote peace on the Korean Peninsula and lay the groundwork for peaceful reunification."

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CNN's K.J. Kwon contributed to this report.