WASHINGTON • The United States and South Korea have scaled down an annual joint military exercise set for spring next year to facilitate nuclear talks with North Korea, US Defence Secretary Jim Mattis said.

"Foal Eagle is being reorganised a bit to keep it at a level that will not be harmful to diplomacy," Mr Mattis said on Wednesday, adding that it would be "reduced in scope".

Foal Eagle, the biggest of the regular joint exercises held by the allies, has always infuriated Pyongyang, which condemned it as preparations for invasion. But the drill - one of the world's largest field exercises involving 200,000 South Korean and some 30,000 US soldiers - was delayed and scaled down last year as diplomatic detente took hold on the Korean Peninsula.

And following a historic summit with North Korean leader Kim Jong Un in Singapore in June, US President Donald Trump announced that Washington would stop holding joint exercises with Seoul, calling them expensive and "very provocative".

Since then, the two allies have suspended most of their major joint exercises including the Ulchi Freedom Guardian in August and Vigilant Ace, slated for next month.

But more recently, progress in talks with the North has stalled, with the US pushing to maintain sanctions against it until its "final, fully verified denuclearisation", and Pyongyang condemning US demands as "gangster-like".

Washington stations 28,500 troops in South Korea to defend it from its nuclear-armed neighbour, which invaded in 1950. But differences are beginning to emerge between Seoul and Washington.

The South's dovish President Moon Jae-in has long favoured engagement with the North, which is subject to multiple UN Security Council sanctions over its nuclear and ballistic missile programmes.

He has dangled large investment and joint cross-border projects as incentives for steps towards denuclearisation, while the US has been adamant that pressure should be maintained on Pyongyang until it fully dismantles its weapons programmes.

Seoul's Defence Ministry said Mr Mattis' comments were in line with their shared view on the need to back diplomacy - but a spokesman added that the question of whether the exercises will take place at all was "still under discussion".

Earlier this month, Pyongyang threatened to "seriously" consider returning to its weapons drive if Washington did not end its tough economic sanctions.

And last month, the North's state media carried a near 1,700-word commentary accusing the US of playing a "double game", implicitly criticising Mr Trump for comments aimed at barring Seoul from lifting sanctions against Pyongyang.

US Secretary of State Mike Pompeo on Wednesday defended Washington's strategy on the peninsula, noting that North Korea had halted missile launches and had not conducted a nuclear test in over a year.

"And I do hope there'll be a summit between the two leaders early in 2019," he said in an interview with KCMO radio.

Pyongyang has declared its nuclear and missile development complete, saying it has no more need for testing. Mr Trump said he hopes to have a second meeting with Mr Kim next year, but talks between Mr Pompeo and a top North Korean official, partly to prepare for the meeting, have been cancelled.

The US said the North axed the talks because they were not ready, and Mr Trump insisted he was in "no rush".

AGENCE FRANCE-PRESSE