This story has been updated to include additional comments from U.S. Secretary of State Mike Pompeo

The United States should be ready to apply “additional pressure on the Kim regime,” Senator Edward J. Markey’s office said on Friday in response to a warning from North Korea’s foreign ministry the day before.

Markey’s office said it had expressed “concern” about the comments attributed Thursday to DPRK Vice Foreign Minister Choe Son Hui, who said Thursday that Pyongyang has “no intention” to meet U.S. demands for further concessions on its nuclear program.

At a special briefing for journalists and diplomats in Pyongyang, Choe also said