Austrian Chancellor Sebastian Kurz has condemned a "disgusting" and "racist" poem, written by a member of his far-right coalition partner, that railed against multiculturalism and compared migrants to rats.

The poem was written by Christian Schilcher, a deputy mayor belonging to the anti-immigration Freedom Party (FPÖ) that forms the other half of the country's ruling alliance.

It used xenophobic imagery to suggest that migrants should assimilate or "quickly hurry away" from their adopted countries, and was written over a drawing of a rat wearing a long black beard and hat.

Kurz -- who has previously come under pressure to denounce the rhetoric and actions of FPÖ politicians -- urged the group to clarify the text, which appeared on Easter Sunday in a regional newspaper belonging to the party.

"The choice of words is disgusting, shows contempt for human beings and is deeply racist," he told Austrian news agency APA.

"The Freedom Party in Upper Austria must distance themselves from this immediately and unequivocally and issue a clarification," he added.

One line of Schilcher's poem reads: "if you mix two cultures ... it's as if you destroy them."

"Just as we live down here, so must other rats, who as guests or migrants ... share with us the way of life, or ... quickly hurry away," the poem also says.

CNN has contacted the FPÖ for comment.

Schilcher apologized for the wording in an interview with regional newspaper Oberösterreichische Nachrichten, claiming he had not considered the historical connotations of the comparison between humans and rats but standing by the central message of the poem.

Comparing Jewish people to rodents was a tactic frequently used in Nazi Germany propaganda.

The poem was published on the same day as Heinz-Christian Strache, FPÖ chairman and Austria's Vice Chancellor, was accused of sharing an article from a website that denies the Holocaust -- putting further pressure on Kurz to distance himself from the party as he prepares to contest next month's European elections. Strache has denied the allegations.

The FPÖ has been in government with Kurz's Austrian People's Party since the country's 2017 election, in which both parties took a hard line against immigration.

Drawing a link between the poem and the allegations against Strache, Pamela Rendi-Wagner, leader of the opposition Social Democratic Party, tweeted: "Kurz must act or he loses all credibility in the fight against racism and anti-Semitism."