"The abrupt announcement of the cancellation of the meeting is unexpected for us and we cannot but find it extremely regrettable," Kim Kye Gwan, North Korea's First Vice Foreign Minister, said in a statement carried by the state-run KCNA news agency.

"We again state to the US our willingness to sit face-to-face at any time in any form to resolve the problem," Kim added.

US President Donald Trump on Thursday called off his planned June summit with Kim Jong Un, blaming "open hostility" from the North Korean regime and warning Pyongyang against committing any "foolish or reckless acts".

In a letter to Kim, Trump announced he would not go ahead with the high-stakes meeting set for June 12 in Singapore, following what the White House called a "trail of broken promises" by the North.

In his Friday statement, First Vice Foreign Minister Kim said the North Korean leader had been preparing for the summit to go ahead.

"Our Chairman (Kim Jong Un) had also said a meeting with President Trump would create a good beginning and had been putting effort into prepartions for it," Kim said.

Just before Trump announced the cancellation of the talks, North Korea declared it had "completely" dismantled its nuclear test site, in a carefully choreographed move portrayed as a goodwill gesture ahead of the summit.

But the chances of success for the unprecedented face-to-face had recently been thrown into doubt.

On Thursday Pyongyang hardened its rhetoric by attacking US Vice President Mike Pence as "ignorant and stupid".

That broadside appeared to hit a nerve with Trump, leading to him abruptly pulling out of the talks.

"Sadly, based on the tremendous anger and open hostility displayed in your most recent statement, I feel it is inappropriate, at this time, to have this long-planned meeting," read Trump's letter to Kim, which was dictated word-for-word by the US leader, according to a senior White House official.