The prospect of further denuclearization talks between North Korea and the United Stated dimmed further over the weekend with U.S. Secretary of State Mike Pompeo refusing to relinquish his role as chief U.S. negotiator, and National Security Adviser John Bolton calling on the North prove it's serious in giving up its nuclear weapons.

The chances of a third Kim-Trump summit this year in the light of these heightened tensions is next to zero, said some analysts.

Taken together, both American actions are Washington's response to North Korea's demand on April 18 that Pompeo no longer is involved in future denuclearization talks. Washington says Pompeo will stay on, take it or leave it. North Korea has yet to respond to the American reply.

North Korea last week called for someone who "is more careful and mature in communicating" to lead the U.S. negotiating panel, according to a state-run propaganda media agency, KCNA.

North Korea's Ministry of Foreign Affairs then commented that "no one can predict" the situation on the Korean peninsula if the United States does not abandon the "root cause" that compelled North Korea to develop its nuclear program.

The future of U.S. engagement with North Korea remains in limbo since the failed Hanoi summit in February, with no sign of direct contact between the two sides.

Pompeo brushed aside North Korea's demand, saying the American negotiators will still be his team. Pompeo also acted as if North Korea hadn't demanded his ouster from the American negotiating team.

"Nothing has changed," bragged Pompeo. "We'll continue to work to negotiate; still in charge of the team. President Trump's obviously in charge of the overall effort, but it'll be my team."

He added U.S. diplomats led by Special Representative for North Korea Stephen Biegun will continue talks aimed at forcing North Korea's denuclearization, which he claims North Korean leader Kim Jong Un committed to last June, which is just not true.

"We will continue to press North Korea to abandon all of its weapons of mass destruction, ballistic missiles related programs and facilities," said Pompeo. "We will continue to enforce all sanctions on North Korea and encourage every country to do so."

Kim last week warned the summit breakdown in Hanoi risked reviving tensions. He also said he was only interested in meeting Trump again if the U.S. leader showed more flexibility. He gave a year-end deadline for a change in attitude. Trump and Pompeo have rejected this demand.

On Saturday, North Korea slammed Bolton's "nonsense" call for it to show it's serious about relinquishing its nuclear weapons, the second its attacked a leading Trump,p official in less than a week.

"Bolton, the national security adviser of the White House, in an interview with Bloomberg, showed above himself by saying such nonsense," said North Korean Vice Foreign Minister Choe Son Hui, according to KCNA.

"Bolton's remarks make me wonder whether they sprang out of incomprehension of the intentions of the top leaders of the DPRK and the U.S. or whether he was just trying to talk with a certain sense of humor for his part, with its own deviation," she said.

"All things considered, his word has no charm in it and he looks dim-sighted to me."