JERUSALEM — Israel’s interior minister declared Günter Grass, one of Germany’s best-known authors, unwelcome in Israel on Sunday, barring him from entering the country for a poem that accused Israel of being a threat to world peace.

“Grass’s poems fan the flames of hatred against Israel and the Israeli people, thus promoting the idea he was part of when he donned an SS uniform,” said the minister, Eli Yishai, referring to Mr. Grass’s admission that he had been a Nazi soldier as a 17-year-old. “His distorted poems are not welcome in Israel. I suggest he try them in Iran where he will find a sympathetic audience.”

Controversy has engulfed Mr. Grass, 84, for the past five days since he published his 69-line poem titled “What Must Be Said” in the German newspaper Süddeutsche Zeitung. The poem assailed Israel for its threats to attack Iran over its nuclear program, called for supervision of Israel’s nuclear weapons and warned that Germany, through its sales of submarines to Israel, risked being complicit in a crime.

While those views are relatively common among European intellectuals, the way in which they were strung together — placing Israel and Iran on the same moral plane, echoing language and themes that have long stirred anti-Semitism — along with Mr. Grass’s own personal history have drawn exceptional anger to the poem.

The issue continued to boil in Germany, where Foreign Minister Guido Westerwelle called comparisons between Israel and Iran “absurd,” and Marcel Reich-Ranicki, the country’s leading literary critic and himself a Holocaust survivor, described the poem as “disgusting.”

In an article in the newspaper Bild am Sonntag, Mr. Westerwelle wrote that Germany had “a historic responsibility for the people of Israel” and underscored the similarities between the countries as democracies as well as the history between their peoples. Mr. Westerwelle also noted that he had traveled to Israel and criticized the country’s West Bank settlements at a news conference in Jerusalem.

“Putting Israel and Iran on the same moral level is not ingenious but absurd,” Mr. Westerwelle wrote.

The discussion in Germany over Mr. Grass’s poem has in large part revolved around the question of whether it is possible for Germans to criticize Israel, which Mr. Grass’s critics call a straw man and a cover for anti-Semitism. Mr. Grass in the poem described the “verdict ‘anti-Semitism’ ” as a reason for silence.

In an interview in the newspaper Frankfurter Allgemeine Zeitung, Mr. Reich-Ranicki, who is 91, said that he did not consider Mr. Grass an anti-Semite but that the poem itself was “a disgrace.” Mr. Reich-Ranicki, who addressed the German Parliament in January on International Holocaust Remembrance Day, said that he feared consequences of the poem’s reception among others interested in criticizing Israel and Jews more harshly.

Many who commented on the dozens, if not hundreds, of German newspaper articles on the topic have jumped to Mr. Grass’s defense. In the comments section of the Frankfurter Allgemeine Zeitung’s Web site, the most recommended comments on an article about the interview are supportive of Mr. Grass and critical of Mr. Reich-Ranicki. “Only in Germany after a valid critique of Israel’s policy of warmongering do you hear the old creak of the camp gates,” wrote one commenter. Another called Mr. Reich-Ranicki a “toady.”

The debate in Germany has reopened old wounds about the country’s past and the question of what Germans can and cannot do and say in light of the Holocaust.

Two days after his poem appeared, Mr. Grass said in an interview that he had meant to focus his attack not so much on Israel as on the policies of Prime Minister Benjamin Netanyahu.

“The man who damages Israel the most at the moment is in my opinion Netanyahu, and I should have included that in my poem,” Mr. Grass said. “What is now an imminent threat is a risk without parallel — a preventive strike, a first strike against Iran, which would have terrible consequences.”

He said that he had often supported Israel, had visited a number of times and wanted “the country to exist and at last find peace with its neighbors.”

Last week Mr. Netanyahu angrily condemned Mr. Grass for equating Israel and Iran and made reference to Mr. Grass’s time as a member of the Waffen-SS.

On Sunday, in addition to Mr. Yishai’s barring of Mr. Grass from Israel, the foreign minister, Avigdor Lieberman, weighed in. He called the poem “an expression of the cynicism of some of the West’s intellectuals who, for publicity purposes and the desire to sell a few more books, are willing to sacrifice the Jewish nation a second time on the altar of crazy anti-Semites.”

He spoke during a meeting in Jerusalem with Prime Minister Mario Monti of Italy.

Tom Segev, an Israeli historian and columnist for the newspaper Haaretz, wrote an article criticizing the poem but opposed the decision to bar Mr. Grass from entering Israel. “It’s very unpleasant because it moves us in the direction of countries like Iran and Syria that apparently give out entry permits according to people’s political views,” Mr. Segev said.

Mr. Grass’ best-known novel, published in 1959, is “The Tin Drum,” a stirring allegorical exploration of the rise of Nazism in Germany and Poland. He was awarded the Nobel Prize in Literature in 1999; the Nobel committee described “The Tin Drum” as a new beginning for German literature “after decades of linguistic and moral destruction.”

Mr. Grass has also shown a willingness time and again to enter the arena of politics, where he campaigned for the left-leaning Social Democrats. He has also long sought to act as a national conscience for the Germans over their Nazi past. When he revealed in 2006 that he had been a Nazi soldier at the end of World War II, something he had kept hidden for decades, he was accused of hypocrisy.