Thousands of Norwegians plan to gather in Oslo to protest against mass murderer Anders Behring Breivik by singing a folk song he hates and which he considers a Marxist indoctrination method.

After an Internet campaign, more than 5,000 people have said they plan to meet at a square near the Oslo courthouse where Breivik is currently on trial for his July 22 attacks that killed 77 people, to sing “Children of the Rainbow” by Norwegian folk singer Lillebjoern Nilsen.

Nilsen and the culture ministers of all five Nordic countries — Norway, Sweden, Finland, Denmark, and Iceland — have also said they would be at the square to participate in the sing-a-long. Other similar events were to take place across Norway. While he has confessed to carrying out the twin attacks, he refuses to plead guilty, saying his attacks were “cruel but necessary” to stop the ruling Labour Party’s “multicultural experiment” and the “Muslim invasion” of Norway and Europe.