The new North Korea policy of the Joe Biden administration is designed to be flexible to enable the "best chance of diplomatic success" by learning from past unsuccessful efforts, a senior US administration official said Thursday.

"We are not going to lay out exactly our diplomatic strategy here and now, I would simply say that we've tried to design it to be flexible," the official told reporters while speaking on condition of anonymity.

"We understand where previous efforts in the past had difficulties, and we're determined to try to learn from those past efforts to give ourselves the best chance of diplomatic success," he said.

After wrapping up its monthslong North Korea policy review last month, the United States said it will not seek a "grand bargain" with North Korea or rely on strategic patience.

The official reiterated the US is open to engagement with the North.

"Our policy calls for a calibrated, practical approach that is open to and will explore diplomacy with the DPRK to make practical progress and increase the security of the United States, our allies and our deployed forces," he said. DPRK stands for the Democratic People's Republic of Korea, the North's official name.

In an exclusive interview with Yonhap News Agency this week, White House czar for Asia Kurt Campbell said the Biden administration will build on a Singapore statement jointly issued by North Korean leader Kim Jong-un and former US President Donald Trump in 2018, in which Kim committed to full denuclearization of his country in exchange for improved relations with the US.

The official, who spoke to reporters on the phone, refused to comment on what that meant.

"I think, at this juncture, it's really not in our interest to preview or comment on specific issues like an end of war declaration in hopes of spurring dialogue," the official said.

"I think the goal here is to understand that this process is likely to be challenging and to give ourselves maximum flexibility in the process with ultimate goals that we will continue to strive for."

The remarks came one day before Biden will hold his first in-person summit with South Korean President Moon Jae-in.

"You can expect that a significant amount of the upcoming visit will be spent discussing the challenges of the DPRK and how our two countries can move forward together in dialogue," the official said of the Moon-Biden summit.

Moon arrived here Wednesday.

The official also highlighted the significance of Friday's summit, noting Moon will be only the second foreign head of state to hold an in-person summit with Biden.

"The visit will highlight the ironclad alliance between the United States and the Republic of Korea and the fact that President Biden's second in-person bilateral meeting is with Korea speaks to our focus and importance of our relationship with the ROK," he said, referring to South Korea by its official name.

"Broadly speaking, the discussions between the two leaders will focus on how both countries can further strengthen our alliance and expand our close cooperation."

On Friday, Moon is also set to attend an award ceremony at the White House where Biden will present a Korean War veteran, Ralph Puckett Jr., with the Medal of Honor, the highest military decoration.

Moon will be the first foreign leader to have ever participated in a Medal of Honor award ceremony, the administration official said. (Yonhap)