Close cooperation between South Korea, Japan and the United States is crucial in dealing with a range of challenges facing the allies in the Indo-Pacific, including the security threat posed by North Korea, a state department spokesperson said Friday.

Ned Price said ways to enhance the trilateral cooperation will also be a major topic for US-Japan discussions next week.

US President Joe Biden is set to hold a bilateral summit with Japanese Prime Minister Fumio Kishida at the White House, after their defense and foreign ministers hold the annual Security Consultative Committee meeting in Washington.

"We have an ironclad relationship with our Japanese allies. That will be on full display next week when we have a Two Plus Two format with our Japanese allies and when the president, prime minister convene at the White House on Friday," the department press secretary said during a press briefing at the Foreign Press Center in Washington.

"The bilateral relationship we have with Japan is indispensable to our shared vision of a free and open Indo-Pacific. But there are certain challenges and the DPRK is at the top of that list, where it's especially important for us to have an effective trilateral relationship as well," he added.

DPRK stands for the Democratic People's Republic of Korea, North Korea's official name.

Price said the Biden administration has been working to "revitalize" the trilateral cooperation since its earliest days, "knowing that the challenges we confront in the Indo Pacific, as well as the opportunities but certainly the challenges, would benefit from a seamless and unified trilateral approach."

"It's a topic of conversation with our ROK allies, just as the threat that the region, Japan, the ROK, other allies and partners face from the DPRK (is) in the context of next week's discussions," he added, referring to South Korea by its official name, the Republic of Korea.

The department spokesperson also highlighted US efforts to help improve human rights conditions in North Korea, despite the post of US special envoy for North Korean human rights being vacant for more than five years.

"I don't have any personnel announcements," he said when asked, adding, "But I can tell you that when we look at our approach to the DPRK, we are taking into account the full array of challenges that we see from that regime and within that regime."

Price insisted that the human rights situation in the North is of "deep concern" to the US.

"So special envoy or not, this is a focus of ours. We, even in amidst of a robust sanctions regime that owes to North Korea's ballistic missile, its ballistic missiles its nuclear weapons program, we seek to do all that we can to support the people of the DPRK," he said. (Yonhap)