The United States is still "hopeful" that a planned summit between U.S. President Donald Trump and North Korean leader Kim Jong-un will go ahead despite the regime's threats to call it off, the White House said Wednesday.

North Korea earlier called the June 12 meeting into question as it slammed ongoing military exercises between South Korea and the U.S. as a provocation and an invasion rehearsal.

The North's first vice foreign minister, Kim Kye-gwan, also said the regime has no interest in discussing a "unilateral" abandonment of its nuclear weapons.

"We're still hopeful that the meeting will take place and we'll continue down that path," White House press secretary Sarah Sanders said in an interview on Fox News. "At the same time we've been prepared that these could be tough negotiations. The president is ready if the meeting takes place and if it doesn't, we'll continue the maximum pressure campaign that's been ongoing."

Trump and Kim are set to meet in Singapore to discuss the denuclearization of the regime.

The North Korean leader has repeatedly expressed a commitment to denuclearizing the Korean Peninsula, but questions remain over whether he would agree to the U.S. goal of a complete, verifiable and irreversible dismantlement of the nuclear program.

It was also unclear what concessions the regime would seek in return. In March, Kim told South Korean officials that he understood that routine military exercises between the South and the U.S. "must continue."

North Korea has long condemned the drills as a dress rehearsal for invasion.

Sanders said the North's warning was "not something that is out of the ordinary."

"Look, this is something that we fully expected," she later added at the White House.

U.S. National Security Adviser John Bolton has called for a dismantlement process similar to the "Libya model" of packing up the country's nuclear facilities and shipping them to the U.S. before giving rewards.

The North Korean vice foreign minister said such talk is not conducive to resolving the issue through dialogue.

"I haven't seen that as part of any discussions, so I am not aware that that's a model that we are using," Sanders told reporters. "I haven't seen that that is a specific thing. I know that that comment was made, but I don't think we are going off of ... there is not a cookie cutter on how this works."

She said there will be a "President Trump model" for North Korea.

"He is going to run this the way he sees fit and we are 100 percent confident ... that he is the best negotiator and we are very confident in that front," the spokeswoman said.

Source: Yonhap News Agency