North Korea yesterday called into question a much-anticipated and unprecedented summit between its leader Kim Jong Un and US President Donald Trump, the South's Yonhap news agency reported.

Pyongyang also cancelled high-level talks due today with Seoul over the Max Thunder joint military exercises between the US and the South, Seoul said.

The US will "have to undertake careful deliberations about the fate of the planned North Korea-US summit in light of this provocative military ruckus", Yonhap quoted the North's official news agency KCNA as saying.

The drills between the two allies' air forces were a rehearsal for invasion and a provocation at a time when inter-Korean relations were warming, it cited KCNA as adding.

The language used is a sudden and dramatic return to the rhetoric of the past from Pyongyang, which has long argued that it needs nuclear weapons to defend itself against the US.

After years of war of word, in a dizzying array of diplomatic steps, North Korea has stunned the world. The biggest so far was his meeting with Kim in the DMZ last month. The Trump-Kim summit is due in Singapore on June 12, with Washington demanding the North give up its weapons in a complete, verifiable and irreversible way.