PYONGYANG, North Korea — North Korea accused the Trump administration on Saturday of pushing a “unilateral and gangster-like demand for denuclearization” and called it “deeply regrettable,” hours after Secretary of State Mike Pompeo said his two days of talks in the North Korean capital were “productive.”

Despite the criticism, North Korea’s Foreign Ministry said the country’s leader, Kim Jong-un, still wanted to build on the “friendly relationship and trust” forged with President Trump during their summit meeting in Singapore on June 12. The ministry said Mr. Kim had written a personal letter to Mr. Trump, reiterating that trust.

The harsh North Korean reaction may have been a time-tested negotiating tactic. Two months ago, a brief blowup between the two countries led President Trump to briefly cancel, then reschedule, his summit meeting with Mr. Kim. But North Korea’s remarks also played to a larger fear: that the summit meeting’s vaguely worded commitment to “the denuclearization of the Korean Peninsula” meant something very different in Pyongyang and Washington.

Distrust on both sides has led the Americans to insist on rapid, deep dismantlement and highly intrusive verification; the North Koreans want an early lifting of sanctions and a formal end to the Korean War, among other steps.