SEOUL - The United States and South Korea announced on Tuesday that their annual joint military drills would go ahead next month, with no significant downsize in scale despite an ongoing diplomatic thaw with North Korea.

The large-scale exercises involving tens of thousands of ground troops are a perennial source of tension between the two Koreas, with Pyongyang condemning them as provocative rehearsals for an invasion of the North.

With talks under way to set up a North-South summit, followed by a proposed face-to-face meet between Donald Trump and Kim Jong Un, there was speculation that this year’s drills might be scaled back to avoid derailing the discussions.

They had already been delayed to avoid clashing with the Pyeongchang Winter Games in the South last month.

But Washington and Seoul said the exercises would kick off on April 1 and be "similar" in size to those of previous years.

"Our combined exercises are defence-oriented and there is no reason for North Korea to view them as a provocation," the Pentagon said in a statement, adding that Pyongyang had been informed in advance of the dates and nature of the drills.

According to a senior South Korean envoy who made a rare visit to Pyongyang earlier this month, Kim had made it clear he "understands" the need for the drills to go ahead.

Such an acknowledgement is in stark contrast to the Kim regime’s denunciations of the exercises in the past. The North has often responded to the drills with its own military actions, and last year fired four ballistic missiles close to Japan.

"Foal Eagle" is a series of field training exercises with approximately 11,500 US forces taking part, together with 290,000 South Korean troops, while "Key Resolve" is a command post exercise using mainly computer-based simulations.

The United States has close to 30,000 troops permanently stationed in South Korea.

Following an extended period of escalating tensions on the Korean peninsula, the Winter Olympics provided the catalyst for a sudden and very rapid approachment that resulted in the announcements of the planned summits.

Those announcements were made by the South Koreans, who have been orchestrating the diplomatic preparations and acting as the messenger between Washington and Pyongyang.

Trump’s administration is pushing ahead with plans for a summit before the end of May, but North Korea has yet to independently confirm it even extended an invitation to leadership talks - maintaining a silence that has raised some concerns in Washington and Seoul.

According to the South Korean envoy who met with Kim in Pyongyang, the North Korean leader also offered to consider abandoning his nuclear weapons in exchange for US security guarantees, and flagged a halt to all missile and nuclear tests while dialogue was under way. - AFP