Only officially recongnized UFO incident by Finnish Government: 1969 UFO sighting in Pori, Finland

I thought this was an interesting, and lesser-known event, that occurred in Finland. From my understanding, this is the only officially acknowledged UFO incident by the Finnish military/government.

https://theufodatabase.com/videos/finnish-air-force-pori-ufo

https://www.is.fi/kotimaa/art-2000000502183.html

https://yle.fi/a/3-5971507

On April 12, 1969, during a Fouga Magister jet training mission at Pori Airport, a flight controller from the Finnish Defence Forces instructed trainee pilot Tarmo Tukeva to check out seven air balloons hovering about 1500-3000 meters above the airport. Upon inspection, Tukeva described the objects as ball or disc-shaped, although he was unable to determine his distance from them. He noted that the objects darted away “at great speed” when he approached. Not only that but, within a minute they were again spotted on radar at Vaasa airport – almost 200 kilometers farther north. Another pilot-in-training, Jouko Kuronen, mentioned that he caught the radio exchanges between the flight controller and Tukeva, and also spotted the objects. The Finnish Armed Forces magazine Ruotuväki drew parallels between the April 12 observations and other instances over water bodies during active military drills, speculating that these might have been “transnational spy planes or aircraft.”

What I find odd about trying to explain these away as spy planes or balloons, is that when they were first observed they were hovering and only upon being approached by Tukeva did they maneuver away. So they seemed to recognize his approach and made an intelligent decision to avoid him. Not only that, they were seen at 1500-3000 feet which seems extremely low for a spy plane. This explanation doesn’t make sense at all.

The plane that was sent to intercept them was traveling at approx. 700kph but couldn’t even get close to them. For these objects to go from basically stationary to well beyond the plane’s speed, allegedly traveling 200km in 60 seconds, this would be a technology we aren’t familiar with or capable of.

Why is this the only official UFO incident that the Finnish government acknowledges? If there was one, certainly there have been more.

I’m surprised there isn’t more about this incident from official/unofficial sources. Any input is appreciated.