WASHINGTON (CNN) — President Donald Trump will not meet North Korean leader Kim Jong Un next month for what would have been a historic diplomatic summit, he announced in a letter to Kim released by the White House Thursday morning.

“I was very much looking forward to being there with you. 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,” Trump wrote. “Therefore, please let this letter serve to represent that the Singapore summit, for the good of both parties, but to the detriment of the world, will not take place.”

Trump and Kim were scheduled to meet in Singapore on June 12, for what would have been the first face-to-face meeting between a U.S. and North Korean leader.

Trump withdrew from the summit after a North Korean vice minister of foreign affairs slammed Vice President Mike Pence on Wednesday as a “political dummy,” the latest harshly worded statement from Pyongyang.

Trump and his aides were infuriated by the statement and wanted to respond forcefully, multiple people familiar with the situation told CNN. The specific and personal targeting of Pence is what irked US officials, three people familiar with the matter said.

The White House was developing a response to the rhetoric on Thursday morning.

On Wednesday, CNN reported the Trump administration was looking to have additional high level talks for assurances from Kim for complete denuclearization before the summit went ahead.

Hours later, a North Korean official lashed out at Pence and said Pyongyang is ready for a nuclear showdown if dialogue with the United States fails.

Choe Son Hui, a vice-minister in the North Korean Foreign Ministry, said if the US continued on its current path, she would suggest to North Korea’s leadership that they reconsider the planned summit between Trump and Kim.

“Whether the US will meet us at a meeting room or encounter us at nuclear-to-nuclear showdown is entirely dependent upon the decision and behavior of the United States,” Choe said in comments carried by North Korea’s state-run KCNA news agency Thursday.

Choe was responding to comments by Pence made Monday during a Fox News interview that she deemed “unbridled and impudent.”

CNN’s Allie Malloy contributed to this report.