"We're still hopeful that the meeting will take place and we'll continue down that path," Sanders told Fox News. "At the same time ... we've been prepared that these might be tough negotiations."
"The president is ready if the meeting takes place. And if it doesn't, we will continue the maximum pressure campaign that has been ongoing."
The North warned it may back out of the high-level summit -- set for June 12 in Singapore -- if the United States pressures it to relinquish its nuclear arsenal.
"If the US is trying to drive us into a corner to force our unilateral nuclear abandonment, we will no longer be interested in such dialogue," first vice foreign minister Kim Kye Gwan said in a statement carried by state media.
In recent weeks Kim has twice met Chinese President Xi Jinping and Pyongyang has announced it will destroy its nuclear testing site next week.
In addition to brandishing threats over the slated meeting with Trump, North Korea cancelled high-level talks due Wednesday with Seoul over the Max Thunder joint military exercises being held between the US and South Korea, denouncing the drills as a "rude and wicked provocation."
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