North Korea on Wednesday threatened the United States about the fate of the summit between Kim Jong-un and Donald Trump, scheduled for June 12 in Singapore, after a joint military exercise between the US and Seoul, BBC reported. Pyongyang cancelled ministerial-level talks with South Korea, which was due to be held on Wednesday.

A report on North Korea’s official Korean Central News Agency said the Max Thunder air combat drills involved US stealth fighters and B-52 bombers, Reuters reported. It said the air drills were a provocation that countered the positive political development in the Korean Peninsula.

“This exercise, targeting us, which is being carried out across South Korea, is a flagrant challenge to the Panmunjom Declaration,” it said, referring to a joint statement issued at a historic peace summit between the two Koreas in Panmunjom village in the South.

KCNA further said: “The United States will also have to undertake careful deliberations about the fate of the planned North Korea-US summit in light of this provocative military ruckus jointly conducted with the South Korean authorities.”

Pyongyang said the US and South Korea had mobilised 100 aircraft in the exercise to make a “pre-emptive airstrike” and “win the air”, The New York Times reported. “There is a limit to our good will. We will be closely watching the attitude of the United States and the South Korean authorities.”

Tensions between the US and North Korea escalated in 2017 after Pyongyang stepped up its efforts to boost its nuclear weapons programme. US President Trump had warned Kim Jong-un a number of times against it, and the two leaders had frequently traded ridicule, insults and threats.

At the Panmunjom summit, the North had announced its intention to denuclearise the Korean peninsula. The two sides also vowed to end the Korean War. On May 12, Pyongyang announced that it will dismantle its nuclear bomb test site between May 23 and 25 to comply with its commitment to stop such tests.