"The IAEA is closely following the recent developments related to the nuclear programme of the Democratic People's Republic of Korea," the Vienna-based UN body said in a statement.

"We hope that these developments will lead to concrete progress regarding the DPRK nuclear issue," it added.

The agency said it had continued to monitor the North's nuclear programme, including through the use of satellite imagery.

"The IAEA stands ready to contribute to its peaceful resolution by resuming our verification activities in the country once a political agreement is reached among countries concerned," the statement said.

North Korea expelled IAEA inspectors from the Yongbyon nuclear site in 2009 and has refused to allow their return.

The agency has condemned North Korea's repeated nuclear tests.

The surprise summit, due to be held by the end of May, comes after months of tension with the reclusive regime testing nuclear and ballistic weapons in defiance of international condemnation and Trump and Kim trading insults.

The IAEA, which covers 168 states and likes to call itself the "atoms for peace" organisation, works to prevent nuclear proliferation and notably oversees the agreement the international community struck with Iran in 2015.