North Korean leader Kim Jong Un said the breakdown in talks with the United States has raised the risks of returning to past tensions, but he is only interested in meeting President Donald Trump again if the United States comes with the right attitude, state media KCNA said on Saturday.

Kim said that he will wait "until the end of this year" for the US to decide, according to KCNA.

"What is needed is for the US to stop its current way of calculation, and come to us with a new calculation," Kim said in a speech to the Supreme People's Assembly on Friday, KCNA said.

Trump and Kim have met twice, in Hanoi in February 2019 and Singapore in June 2018, building goodwill, but failing to agree on a deal to lift sanctions in exchange for North Korea abandoning its nuclear and missile programmes.

Trump said on Thursday he is open to meeting Kim again, but in his speech on Friday, the North Korean leader said the outcome in Hanoi has forced him to question the strategy he embraced last year of international engagement and economic development.

"The second DPRK-US summit in Hanoi in February raised strong questions about whether the steps we took under our strategic decision were right, and gave us a sense of caution about whether the US is really trying to improve the DPRK-US relationship," Kim said, using the initials of North Korea's full name, the Democratic People's Republic of Korea.

In Hanoi, the United States came with "completely unrealisable plans" and was "not ready to sit with us face-to-face and solve the problem," Kim said.

"By that sort of thinking, the US will not be able to move us one iota even if they sat with us a hundred thousand times, and will not be able to get what it wants at all," he said.

Kim said his personal relationship with Trump is still good, but he had no interest in a third summit if it is a repeat of Hanoi.

"The US said recently that it is thinking again of a third DPRK-US summit and have been strongly implying problem-solving through dialogue," Kim continued. 

"But they continue to ignore the basic way of the new DPRK-US relations, including withdrawing hostile policies, and mistakenly believe that if they pressure us to the maximum, they can subdue us."

At a summit with South Korean President Moon in Washington on Thursday, Trump expressed a willingness to hold a third summit with Kim, but said Washington would leave sanctions in place on Pyongyang.

Last month, a senior North Korean official warned that Kim might rethink a moratorium on missile launches and nuclear tests in place since 2017 unless Washington makes concessions such as easing sanctions.

- Reuters