Seoul, Nov 1 (IANS): South Korea and the US kicked off a combined annual air exercise Monday, in a low-key manner apparently to back ongoing diplomacy to resume dialogue with North Korea, a military source said.

For the five-day exercise, the allies mobilised some 100 air assets each, including F-15K and KF-16 jets from South Korea, and F-16s from the US, Yonhap News Agency quoted the source as saying, noting no military assets were deployed from the US mainland this time.

The allies have regularly held the air exercise in a scaled-down, low-key manner since they suspended the large-scale Vigilant Ace exercise to support peace efforts on the Korean Peninsula.

The South Korean Air Force declined in public to elaborate on the manoeuvers, only saying that allied exercises are carried out in a "balanced manner" under the annual plan.

"We cannot comment on the exercise as it is one that is not disclosed to the media," an Air Force official told Yonhap News Agency.

North Korea has long denounced the allies' military drills as a war rehearsal for an invasion and used them as an excuse for provocations.

The reclusive regime recently called on the allies to drop "double standards", slamming Seoul and Washington for defining its missile activities as "provocations" while rationalizing their own as deterrence.