A couple walks past a television showing a report on Jang Song Thaek, North Korean leaders' uncle, at a railway station in Seoul December 3, 2013.
A couple walks past a television showing a report on Jang Song Thaek, North Korean leaders' uncle, at a railway station in Seoul December 3, 2013.Reuters

The execution of Chang Song-thaek, North Korea's once powerful leader and the uncle of Supreme leader Kim Jong-un on Thurday jolted the United States, which has now warned the East Asian country against a possible series of provocative acts in defiance of the international system.

The US said that it was consulting its regional allies, after North Korea announced on Thursday that it had executed Chang for "acts of treachery", a move that has raised concerns across the international community of a possible instability and a start of a new conflict in the reclusive and controversial nuclear-armed nation.

State Department spokeswoman Marie Harf said that the execution of Chang who was once considered a mentor to the young Leader of North Korea, was "an incredibly brutal act" and one among many other facts that "underscores the horrific human rights record of the North Korean regime".

"We're going to increase our discussions with our allies and partners in the region about the internal situation in North Korea," Harf told reports in Washington. "North Korea has a choice between continuing down the path of isolation and impoverishment of its own people or meeting its obligations and coming back to the international system."

Pointing out that such an act would not be considered by the international community as being in the interest of regional stability, she said that the US "would urge the North Koreans not to take provocative acts".

This comes only hours after the White House quickly reacted to the news and said that the incident only showed the true nature of the North Korea regime.

"This is another example of the extreme brutality of the North Korea regime," Patrick Ventrell, a spokesman for the White House's National Security Council said on Friday. "We are following developments in North Korea closely and consulting with our allies and partners in the region."

On Friday, the state owned KCNA announced the execution of Kim's uncle in a detailed and lengthy report which called Chang a "despicable human scum" and "worse than a dog"

The decision to execute him "served as sledge-hammer blow brought down by our angry service personnel and people on the head of Jang, an anti-party, counter-revolutionary factional element and despicable careerist and trickster," it said in the strongly worded statement.

Chang was seen in rare pictures, earlier in the week, being removed from a communist party politburo meeting by armed guards. The once powerful diplomat who often handled high profile talks with China, North's only major ally was executed on Thursday, shortly after a special military trial announced him guilty of attempting to overthrow the state, KCNA said.

The developments come after years of international talks aimed at nudging North Korea to denuclearize and reduce its threats of a nuclear war towards international community have failed.

In February 2013, the unpredictable nuclear-armed nation threatened of an "all-out nuclear war" against South Korea and US and warned of reducing Washington and Seoul to "ashes" after the international community slapped the nation with increased sanctions against the controversial February 12 under-ground detonation of a nuclear bomb.