The Trump administration is hopeful its summit with North Korea will go ahead, despite threats of cancellation.
A White House spokesperson said the US president remained ready.
Hours earlier, North Korea released an angry statement saying it might pull out of the meeting if the US insisted it gave up its nuclear weapons.
The highly anticipated meeting between Mr Trump and North Korea’s Kim Jong-un is due to take place on 12 June.
“The president is ready if the meeting takes place,” said White House spokesperson Sarah Sanders. “If it doesn’t, we’ll continue the maximum pressure campaign that’s been ongoing.”
When asked if it would go ahead, Mr Trump later said: “We’ll have to see”.
He reiterated that the US would still insist on denuclearisation.
The groundbreaking agreement for Mr Kim and Mr Trump to meet came about as North Korea said it was committed to denuclearising the Korean peninsula.
Exactly what that would entail has remained unclear but North Korea has invited foreign media to witness the dismantling of its main nuclear test site later this month.
What suddenly upset North Korea?
North Korea’s statement, carried by state media, said the country had had high expectations from the summit, but it was “totally disappointed” by recent reckless remarks from the US.
It pointed the finger squarely at US National Security Adviser John Bolton.
“We do not hide our feeling of repugnance towards him,” said the statement, which was written by Vice-Foreign Minister Kim Kye-gwan.
In a television interview at the weekend, Mr Bolton said North Korea could follow a “Libya model” of verifiable denuclearisation, but this alarms Pyongyang, which watched Libya’s Colonel Gaddafi give up his nuclear programme only for him to be killed by Western-backed rebels a few years later.