North Korea announced this week that leader Kim Jong Un's uncle by marriage, Jang Song Thaek, was executed, and now analysts are trying to figure out the motive behind the unexpected move.

BEIJING – Jang Sung Taek, the uncle by marriage of North Korean leader Kim Jong Un, was executed Friday for attempting to seize power for himself, the country's official news service reported early Friday.

In a rambling report, the Korea Central News Agency denounced the “despicable human scum Jang, who was worse than a dog’’ and said that he had attempted to “overthrow the state by all sorts of intrigues and despicable methods with a wild ambition to grab the supreme power.”

The execution is the first by North Korea in decades of a top echelon official and raises questions about the stability of the increasingly erratic government.

PHOTOS: North Korean leader Kim Jong Un

The 67-year-old Jang was married to Kim Kyong Hui, the daughter of North Korean founder Kim Il Sung and the only full sibling of the late leader Kim Jong Il. He was widely considered the second most important person in the country and had installed many relatives and cronies in key positions in the government and military.

Since the Kims were famously insecure about leaving North Korea, Jang frequently represented the country abroad, even visiting Seoul in 2002 where he impressed South Korean officials with his economic savvy. He also was a key interlocutor with the Chinese, who considered him the most reliable figure in North Korea's eccentric leadership.

North Korean defectors in Seoul said that Jang’s wife, who is suffering from acute liver disease, assisted in bringing down her husband to maintain the hereditary “blood line” of the Kims.

A report by the North Korea Strategic Information Service Center, run by a defector, Lee Yun-keol, said that Kim Jong Un’s 32-year-old brother, Kim Jong Chul, held the gun when two of Jang’s underlings were arrested.

On Sunday, the now 30-year-old Kim Jong Un presided over a special meeting of the politburo at which Jang was stripped of all his posts and in a spectacular televised scene, yanked by his armpits and dragged out of a chair.

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Twitter: @BarbaraDemick

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