The United States said Friday that North Korea's recent actions have risen the bar for a resumption of dialogue as it called on Pyongyang to address concerns on weapons but also human rights.

North Korea engaged in some of its most fiery rhetoric in years after conducting its third nuclear test in February, but tensions have since eased with attempts -- ultimately unsuccessful -- to restart talks with South Korea.

Glyn Davies, the US pointman on North Korea policy, said the United States was exasperated with Pyongyang after it snubbed attempts by President Barack Obama's administration to reach out in 2009 and again in 2012.

"The United States will not accept North Korea as a nuclear-armed state. We will not reward the DPRK for the absence of bad behavior," Davies said, using the North's official name of the Democratic People's Republic of Korea.

"Nor will we tolerate North Korea provoking its neighbors. These positions will not change," he said in Washington at the Woodrow Wilson International Center for Scholars, a think tank.

Davies repeated US calls on North Korea to take steps to end its nuclear weapons program in line with previous agreements -- and said that this year's crisis increased Washington's hesitancy to engage again.

"We've long made clear that we are open to improved relations with the DPRK if it is willing to take concrete actions to live up to its international obligations and commitments -- though given the events of this past year, the bar for a resumption of meaningful engagement is now certainly higher."

Satellite images analyzed by two private institutes have found that North Korea is pushing ahead with work on its nuclear program and could soon restart a reactor to produce plutonium.

Davies also voiced concern over human rights.

Advocacy groups have long accused the United States and its allies of putting its focus solely on North Korea's nuclear weapons and ignoring a totalitarian system often considered the world's most draconian.

"US-DPRK relations cannot fundamentally improve without sustained improvement in inter-Korean relations and human rights," Davies said.

Frank Jannuzi, the head of Amnesty International's Washington office, applauded Davies for taking a "more holistic approach" to North Korea.

"The bottom line is that 20 years of diplomacy focused on plutonium have not gotten the results that the United States wants," he said.

"Amnesty International believes that a policy focused more on people and less on plutonium will serve both objectives -- denuclearization and peace."

The United Nations Human Rights Council agreed in March to set up a commission of inquiry to see if violations in North Korea amounted to crimes against humanity, a move led by Japan and the European Union.

Davies said the United States wanted to coordinate with South Korea and Japan as well as other nations including China, North Korea's closest ally which has been unusually vocal in recent criticism of Kim Jong-Un's regime.

The State Department said Davies will meet Wednesday in Washington on North Korea policy with his counterparts from Japan and South Korea, close US allies which have seen a recent spike in historical friction between each other.

Davies said it was "now more crucial than ever" for the United States and Pyongyang's neighbors to work together "to prevent North Korea from exploiting any perceived differences in our unified position."

North Korea has long sought one-on-one talks with the United States aimed at a peace treaty, which it sees as vital to preserving its communist dynasty.