The US has urged Pyongyang to avoid any provocative acts following the execution by North Korea of a once-powerful political figure.
North Korea announced on Thursday that it had executed Chang Song-thaek, the uncle of leader Kim Jong-un, for "acts of treachery".
The BBC reports the move has raised concerns of instability in the secretive and repressive nuclear-armed country.
The US said it was consulting its regional allies.
State Department spokeswoman Marie Harf said she would not speculate on what might be happening within the North Korea regime, but that the execution of Mr Chang had been "an incredibly brutal act" which "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," Ms Harf told reporters 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," said Ms Harf.
She said the US "would urge the North Koreans not to take provocative acts" as it was "not in the interest of regional stability".
International talks aimed at convincing the North to denuclearise and reduce its threatening posturing towards the international community in exchange for aid have repeatedly failed.
Mr Chang was married to the sister of late leader Kim Jong-il, and is believed to have mentored Kim Jong-un when he succeeded his father in North Korea in 2011.
He had been seen as the second-most important figure in the country, holding several key posts, but this week was dramatically removed from a special party session by armed guards and stripped of all his titles.
On Thursday, the state news agency KCNA said he had admitted at a military trial to trying to overthrow the state, and had been executed immediately.