Koivisto: No Karelia offer

As you'll no doubt remember, Kainuun Sanomat recently claimed that Russia had offered to return Karelia to Finland and that then President Mauno Koivisto turned them down. Koivisto stayed mum for a while, but now he's speaking and he's not amused:

"No offers were made by the Soviet Union, or after that, by Russia, for re-examining the border, nor were there any proposals from Finland. No working groups were set up by me, and I do not know that any others would have done so either. There is no foundation to this", Koivisto said in an interview with Helsingin Sanomat at his home in Helsinki.

You can't accuse him of making a non-denial denial.

Meanwhile Kainuun Sanomat has let it be known (fi, link to Google cache 'cause the original is dead) that Jaakko Blomberg, back then the Under-Secretary of State for Political Affairs at the Ministry for Foreign Affairs, told them about the working group. Blomberg has denied knowledge of such a group to several media outlets.

I find this a rather strange story. It's difficult to figure out who's telling the truth here, because neither option makes much sense. I'm currently inclined to think that someone misunderstood something or someone else misspoke. On the other hand, Kainuun Sanomat is an average Finnish regional daily. What incentive would they have to do something as awfully risky as lie about what Blomberg said to their reporter? Alternatively, what incentive would Blomberg have to fib? To better assess the situation, one would need to find out what precisely Blomberg said.