US President Donald Trump said Friday he has canceled Secretary of State Mike Pompeo's upcoming trip to North Korea because of a lack of progress in dismantling the North's nuclear weapons program.

Trump wrote the message on Twitter a day after Pompeo announced that he will be traveling to Pyongyang next week to continue negotiations on the denuclearization of the regime.

"I have asked Secretary of State Mike Pompeo not to go to North Korea, at this time, because I feel we are not making sufficient progress with respect to the denuclearization of the Korean Peninsula," Trump said.

"Secretary Pompeo looks forward to going to North Korea in the near future, most likely after our Trading relationship with China is resolved," he continued. "In the meantime I would like to send my warmest regards and respect to Chairman Kim. I look forward to seeing him soon!"

Trump and North Korean leader Kim Jong-un agreed at their historic summit in June that North Korea would work toward the "complete denuclearization" of the Korean Peninsula in exchange for security guarantees from the US

Negotiations to implement the deal have stalled as Washington demands concrete steps toward denuclearization and Pyongyang insists on formally ending the 1950-53 Korean War, which ended with an armistice.

Pompeo would have been making his fourth trip to Pyongyang this year, and this time with his newly appointed special representative for North Korea, Stephen Biegun.

Trump again accused Beijing, a key ally and benefactor of the North, of hampering the denuclearization process, saying in his series of tweets that he believed that was "because of our much tougher Trading stance with China."

The US and China have been in an escalating trade war, with both sides slapping tariffs on each other.

Meanwhile, Chinese President Xi Jinping is rumored to be planning his first visit to Pyongyang around the Sept. 9 anniversary of North Korea's founding.

The announcement and cancellation of Pompeo's trip comes amid persistent skepticism that Kim is serious about abandoning his nuclear weapons and ballistic missile programs.

Although North Korea has taken steps to dismantle its only known nuclear test site and a major missile engine testing site, experts say they are hard to verify without outside inspection.

In a report published Monday, the United Nations' nuclear watchdog, the International Atomic Energy Agency, expressed "grave concern" over North Korea's continued activities at the Yongbyon nuclear site.

"North Korea never agreed to unilateral denuclearization at the Singapore summit, no matter how much we want to believe that they did," Ken Gause, a North Korea expert at CNA Corp., said in an email to Yonhap.

Pompeo's planned trip to North Korea, according to Gause, "did not make much sense" because there was no indication Kim had changed his mind, and the Trump administration was willing to meet only if there was something substantive to discuss.

"Now, I am beginning to think that this was a tactic by the Trump administration to pressure North Korea into becoming more forthcoming in terms of concessions," he said in an email to Yonhap. "When it became clear that Pyongyang was not going to budge, Trump called off the trip, which would have been an embarrassment and led to many questions if it had been a repeat of Pompeo's last trip, which came away with nothing."

In May Trump called off his Singapore summit with Kim before putting it back on.

On the possibility of a second summit, he told Reuters in an interview this week that it's "most likely" to happen, but didn't provide details. (Yonhap)