WASHINGTON, March 18 (Xinhua) -- U.S. Secretary of State Mike Pompeo said on Monday that the United States will "re-engage" with Kim Jong Un, top leader of the Democratic People's Republic of Korea (DPRK), over issues of mutual concern.

Pompeo made the remarks in an interview with B98 FM, a radio station of the U.S. state of Kansas via teleconference.

"We believe we're still moving forward. It's certainly difficult - we knew it would be. It's been a decades-long challenge," he said, according to the interview transcript circulated by the State Department.

"But we have the toughest economic sanctions in history," Pompeo said, adding that there was the most promising diplomatic engagement in history as well.

"And so we made a little bit more progress in Hanoi," he said, referring to the second summit between U.S. President Donald Trump and the DPRK top leader.

"We'll re-engage with him. It's incredibly important that we take down the threat not only for America and for Kansas, but for the entire world," said the U.S. top diplomat.

Pompeo said on Friday that Washington is still hopeful for continued talks with Pyongyang, confirming that there is ongoing negotiation between the two sides.

After ending the summit in Hanoi on Feb. 28 without reaching an agreement, Trump told a press conference that Kim demanded relief from sanctions against Pyongyang "in their entirety" in exchange for denuclearizing a "large portion" of the DPRK's nuclear program, something the United States could not agree to.

Dismissing Trump's claim, DPRK Foreign Minister Ri Yong Ho has said that DPRK only proposed partial removal of the sanctions, wanting those impeding the livelihood of their people to be removed first.