North Korea on Friday said nuclear negotiations with the United States will “never resume” unless the Donald Trump administration stops what Pyongyang called unilateral demands for disarmament, AP reported.

“Unless the United States puts aside the current method of calculation and comes forward with a new method of calculation, the [Democratic People’s Republic of Korea] DPRK-US dialogue will never be resumed,” a statement published by an unidentified spokesperson for North Korea’s foreign ministry said. “By extension, the prospect for resolving the nuclear issue will be much gloomy.”

Tensions between the two countries escalated in the recent weeks after North Korea fired short-range missiles earlier this month and the US seized a North Korean cargo ship for violating international sanctions.

In February, talks between the United States and North Korea in Hanoi, Vietnam, ended without an agreement after Kim had sought sanctions relief in return for the partial dismantling of North Korea’s nuclear programme. Since then Kim has accused Washington of acting in “bad faith”, and given it until the end of the year to change its approach.

However, Trump and other US officials have brushed that aside, calling for Kim to take action on a commitment to denuclearise.

“They [North Korea] wanted the sanctions lifted in their entirety and we couldn’t do that....sometimes you have to walk, and this was just one of those times,” Trump had said.

Th summit in Hanoi was the second that Trump and Kim held. The two leaders had met for the first time on June 12 last year in Singapore, following which Kim had committed to the “complete denuclearisation” of the Korean Peninsula.