The South Korean army said it had discovered an “unknown object” flying near the border with North Korea, hours after a historic meeting between US President Donald Trump and North Korean leader Kim Jong-un.

A radar monitoring the “traces of unknown body flight” on Monday covered the central part of the demilitarized zone dividing the two Koreas, the South Korean Joint Chiefs of Staff said.

Hours ago, Trump became the first US president to set foot on North Korean soil when he met North Korean leader Kim Jong-un in the northern part of the demilitarized zone separating the two countries on the Korean Peninsula.

The two leaders agreed to resume working-level talks on Pyongyang’s nuclear program.

The demilitarized zone, the most heavily guarded border in the world, where the two Koreas have already exchanged fire from time to time, before North Korea enters talks on its nuclear program.

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— Donald J. Trump (@realDonaldTrump) July 1, 2019