Reuters said the increasingly popular Swedish anti-immigration party suffered a blow when a senior official resigned after a film showed him using offensive language about immigrants.

The party describes itself as a democratic, socially conservative, nationalist party, which had "zero tolerance" for "extremists" and racists. But a a film clip showed senior SD member Erik Almqvist using heavily racist words like “darkie”, “cunt” and “darkie-lover” and other vocabularies used to describe immigrants in a derogatory manner.

The video clip was first published by the tabliod Expressen. The party announced that Almqvist will step down as the party's economic policy spokesman over the racist statements.

"This is not a good day. It could be the worst day in my life, politically and personally," Sweden Democrats party leader Jimme Åkesson told a news conference.