North Korea is willing to restart talks with the United States in late September over its nuclear programme, but warned that chances of a deal could end unless Washington takes a fresh approach.

The North Korean leader, Kim Jong-un, agreed in a 30 June meeting with Donald Trump to reopen working-level talks stalled since their failed February summit in Hanoi, but this has yet to happen despite repeated appeals from Washington.

In a statement carried by North Korea’s official KCNA news agency, the deputy foreign minister, Choe Son-hui, said Pyongyang was willing to have “comprehensive discussions” with the United States in late September at a time and place agreed between both sides.

Asked for comment, a US state department spokeswoman said: “We don’t have any meetings to announce at this time.”

On Sunday, Mike Pompeo, the US secretary of state, said he hoped to return to denuclearisation talks with North Korea in the coming days or weeks.

But Choe highlighted that Washington needed to present a new approach or the talks could fall apart again.

“I want to believe that the US side would come out with an alternative based on a calculation method that serves both sides’ interests and is acceptable to us,” Choe said.

“If the US side toys with an old scenario that has nothing to do with the new method at working-level talks which would be held after difficulties, a deal between the two sides may come to an end.”

In April, Kim set a year-end deadline for the United States to show more flexibility in talks, which broke down in February over US demands for North Korea to give up all of its nuclear weapons and Pyongyang’s demands for relief from punishing US-led international sanctions.

The end-of-September timeframe would coincide with the annual United Nations general assembly in New York, which Pompeo is due to attend. North Korea’s mission to the United Nations said last week that the foreign minister, Ri Yong-ho, would not attend “due to his schedule”.

North Korea has demanded that Pompeo be replaced with a “more mature” person in the US negotiating team, while lauding the rapport built between Kim and Trump in three meetings since June 2018.

The US special representative for North Korea, Stephen Biegun, led working-level talks with North Korea in the run-up to the failed Hanoi meeting.