On 12 April 1969, Finnish Air Force controllers directed pilots to intercept an object near Pori Airport, and the pilots reported a disc. The object identity was never settled.

Pori matters because it is a military intercept report with named pilot testimony — a Nordic case whose object identity remains unresolved.
During a Fouga Magister training mission at Pori Airport, Finnish Defence Forces controllers directed the pilots to investigate an object.
Documented
The training mission and the directive are documented.
The pilots reported observing a disc. The Finnish Defence Forces recorded the event.
Documented
The disc report is documented.
The object identity remains disputed, with aircraft or atmospheric readings proposed. No photograph or radar data is publicly established.
Debated
The object identity is disputed.
The case rests on military testimony. No photograph or radar is publicly established.
Unverified
Any extraterrestrial origin is unverified.
These sources do different jobs: the Finnish Defence Forces record is the official account, and Wikipedia compiles it. Neither establishes the object identity.
The Finnish military record.
The compiled reference.