South Korea, US Quietly Hold Joint Air Exercises amid Calls for Talks with North Korea

The exercises, previously called Vigilant Ace, once mobilized tens of thousands of troops and hundreds of cutting-edge fighter jets, bombers and other warplanes.

But the programme has been scaled back since 2017 to facilitate talks aimed at ending Pyongyang's nuclear and missile programmes in return for US sanctions relief, Reuters reported.

The allies began the drills, which will last five days, without announcing or naming them. Yonhap said that some 100 aircraft were dispatched from each side, including South Korea's F-15Ks and KF-16s and US F-16s, but that no equipment or soldiers from the US mainland would join the exercises.

A South Korean air force spokesman declined to confirm the report.

The drills came after North Korea fired a submarine launched ballistic missile, the latest in its recent series of weapons tests.

The reclusive country sees exercises in the South as a rehearsal for war, and severed inter-Korean hotlines when the allies held regular summer training in August, accusing Seoul of "perfidious behavior".

The US envoy for North Korea, Sung Kim, slammed the test as "concerning and counterproductive" during his visit to Seoul last week and urged Pyongyang to accept offers to talks.

The North has so far rebuffed US overtures, accusing Washington and Seoul of applying "double standards" by criticizing its weapons programmes while talking diplomacy and stoking tension with their own military activities.