White House press secretary Jay Carney on Friday said reports that North Korean leader Kim Jong Un had executed his uncle provided “another example of the extreme brutality” of the regime.

Carney said the reported execution of Jang Song Thaek highlighted “the values of the regime, their low regard for human life.”

He added that Pyongyang had “what is probably the worst human rights record in the world, and that is saying something.”

Carney though cautioned that the White House “can’t independently verify” the execution. “But we have no reason to doubt the official report that he has been executed.”

Kim’s uncle-by-marriage was viewed as the second most important figure in the country. North Korea’s state media announced on Friday that Jang had been executed for crimes against the state.

The release was full of colorful and extreme rhetoric, with the state calling Jang “despicable human scum.”

The execution of a family member and one who had been a close, trusted adviser of his father, led some to question if Kim was making a show of power to consolidate his hold on the country or to ward off a threat from other insiders.

Tensions with North Korea have flared after Pyongyang conducted a number of missile tests inviting additional U.S. sanctions.

Earlier this month an 85-year old U.S. veteran traveling in North Korea was briefly detained before being released.

The administration is also calling on North Korea to release another American, Kenneth Bae, who has been sentenced to hard labor on espionage charges human rights groups say have been trumped up.