"The debate about our connection to Anders Behring Breivik in Norway dropped away a long time ago in Norway because we pointed out that he resigned because he was disappointed that the party was not what he thought it was," the party's deputy leader Ketil Solvik-Olsen told TV2.
"We want to emphasize that while we want stricter asylum policies, we are not, as is often claimed in the media, against immigration."
The party has enlisted the help of Frank Aarebrot, professor of comparative politics at Bergen University.
"It's important that the Progress Party get a fair treatment, and I do not they will get that while they're bunched together with Breivik," Aarebrot, who is a member of the Labour Party, told Aftenposten.
"It is unreasonable to compare the Progress Party with the Danish People's Party, the Sweden Democrats and the True Finns," he added.
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The press conference will be held on Tuesday at the party's headquarters.
Solvik Olsen and the party's youth leader Himanshu Gulati will be present.