It was claimed to be the work of Ukrainian SF, so saboteurs...
Keep in mind it could be a diversionary announcement.
When the US shot down Yamamoto they said he had been seen boarding the plane by a local islander, when in reality his itinerary had been intercepted and decoded by the US.
Ukraine has indigenous ballistic missiles with a much longer range than the Tochka-U called Hrim-2 (Grom-2). They also hit a space search radar in Crimea recently. It is possible they are keeping the use of ballistic missiles secret to avoid search, eventual detection of, and a Kinzhal strike on the bases and maintenance facilities for these missiles.
It is kind of hard to imagine SOF running around the airfield planting bombs, having them undiscovered until daytime, and then detonating them. At this point in the war it is hard to imagine an airbase being that empty and unguarded.
Another possibility is ATACMS, with SOF being used to keep their delivery secret and avoid escalation. We didn't know they had AGM-88s until the Russians posted photos of the wreckage, after all, so definitely could be more weapons being supplied that aren't listed in the public announcements.