A tongue-in-cheek suggestion by Israels U.N. ambassador escalated into a war of words between the United Nations and New York Mayor Ed Koch last week over the status of a local landmark -- and the continuing presence of the global organization in the city.

The controversy was launched by a throwaway line from Israeli Ambassador Yehuda Blum, just before the General Assembly voted 86-21 for a resolution urging isolation of Israel and laying the groundwork for its expulsion from the United Nations.

He suggested that because of U.N. "degeneration and perversion," the peaceable quotation from the Jewish prophet Isaiah -- "They shall beat their swords into plowshares..." -- should be erased from the city-owned monument across from U.N. headquarters.

Koch, who has won popularity in New York's large and pro-Israeli Jewish community for his criticism of the United Nations, and who is contemplating running for governor, picked up on the proposal. Rather than expunge the quotation on the granite monument, commonly called the Isaiah Wall, Koch suggested adding "a statement which would reflect all indignation and outrage at the hypocrisy of the U.N."

As the mayor leafed through the Old Testament, a New York Times editorial, titled "Isaiah Amended," offered a few suggestions.

Why not add Isaiah's phrase preceding the plowshares line: "And He shall judge among the nations, and shall rebuke many people," the newspaper asked, or, "How is the faithful city become an harlot! it was full of judgment; righteousness lodged in it; but now murderers." But The Times cautioned that readers of the last one might think it referred to "murderers not in yonder house of nations but on the streets of Koch's own domain."

A junior U.N. official, Hans Janitschek, leapt into the fray. An Austrian journalist hired by thensecretary general Kurt Waldheim to promote the U.N. image, he earlier had suggested transformation of Alcatraz Island into a U.N. museum.

Last week, Janitschek told a local television reporter: "If the mayor of New York and if the people of New York want us out of New York, I think the U.N. would have to think about it very seriously."

Koch retorted, "The decision as to whether they leave or not is theirs. If the U.N. would leave New York, nobody would ever hear of it again."

Even the Soviet newspaper Pravda has joined in. The paper criticized Koch Monday and suggested his statements were made to woo the "Zionist lobby of New York" in his campaign for governor, The Associated Press reported.

["What surprises one is that Washington did not even think of checking the overweening mayor who insults in public the United Nations organization, the competent international forum," Pravda wrote.]

U.N. spokesman Francois Giuliani, seeking to end the controversy, said the United Nations was not considering leaving the city and Janitschek's statement did not reflect Secretary General Javier Perez de Cuellar's views. But Giuliani said a get-acquainted lunch between the mayor and the new secretary general would be put off indefinitely because of a scheduling conflict.

City Commissioner Gillian Sorensen said that "given the tension and the tumult of the last few days, it was not a propitious moment to sit down and talk." She said she told Koch and U.N. officials that it "would be useful to de-escalate this."

In U.N. corridors, however, most diplomats displayed irritation at Koch. Clovis Maksoud, the representative of the Arab League, said the mayor's plan to change the inscription "for his own political purposes" was "petty harassment."

He warned, however, that "increasing harassment may lead many of us to think about a change of venue for the U.N."

A British diplomat, who did not want to be named, called the controversy "a lot of rubbish" and the mayor's proposal "absurd."

The only diplomat to voice support for Koch was the U.S. deputy representative, Kenneth Edelman, who said of the controversy: "It's fun and he's a fun mayor. If they change the inscription, such a symbolic gesture would prompt a larger discussion of the costs and the benefits of the U.N. to the U.S. itself -- and that would be a healthy thing."