US President Donald Trump and South Korean President Moon Jae-in will meet in April in Washington AFP/Nicholas Kamm

Moon has long backed a policy of engagement with nuclear-armed, sanctions-hit Pyongyang and was instrumental in brokering talks between Trump and North Korean leader Kim Jong Un.

But the failure of Kim and Trump to reach an agreement in Hanoi on curtailing Pyongyang's nuclear programme in exchange for relaxation of sanctions has raised questions over the future of the process.

Moon will visit Washington for two days from Apr 10, an official from the South's presidential Blue House said.

"The two leaders will have in-depth talks ... to coordinate their stance on setting up a peace regime on the Korean peninsula through complete denuclearisation," Yoon Do-han, the senior presidential press secretary said Friday.

Earlier this month, Pyongyang abruptly pulled its staff out of an inter-Korean liaison office, but the officials came back to the joint facility in the Northern city of Kaesong days later.

Their return came after Trump announced he had "ordered" the withdrawal of additional sanctions - without identifying the measures - against Pyongyang by the US Treasury./.

VNF/AFP