The 17 year-old Iceland U21 international was watched by United scouts last week in victory over Varbergs Bois,
And NT-Sport reports a Liverpool scout was in attendance for last night's 2-2 draw with AIK.
Asked about the presence of Liverpool in the stands, Bergmann Johanesson smiled: "Great fun, great fun, but I only focus on trying to help IFK Norrkoping into the European places.
"That is what I think about every day and we will do it together."
Meanwhile, Bergmann Johannesson's cousin Jóhannes Kristinn Bjarnason, 15, is set for trials with IFK this week. Like Isak, Kristinn Bjarnason hailed from the Akranes academy.
"My cousin. Very good midfielder and striker. He is much stronger than I was when I was 15. I would say that he is better than I was," added Bergmann Johannesson.