WASHINGTON — Jewish leaders and the State Department are moving to dispel concerns that the indictment of an 84-year-old retired military engineer for passing nuclear secrets to Israel will rupture America’s relationship with the Jewish state.

Responding to queries from reporters concerning the FBI’s arrest of Ben-Ami Kadish, in New Jersey, the State Department’s deputy spokesman suggested that the 23-year-old case had no impact on American national security today and was connected to the case of a convicted spy, Jonathan Pollard. Mr. Kadish’s alleged handler, who served as a scientific attaché at Israel’s consulate in Manhattan, is also said to have worked with Pollard.

“This case, as well as the Pollard case, date from the same period,” the State Department official, Thomas Casey, said. “I understand there’s at least a connection between them. I think, at the time of the Pollard case, there was a lot of discussion about what implications this had or didn’t have for U.S. national security. I’m not aware that this latest arrest and indictment changes that assessment.” He added: “I don’t think, as far as I know, this fundamentally changes what we understood or what we learned to be the issues involved during that first case back in the mid-1980s.”

The Israeli government learned of the arrest yesterday at a meeting at its embassy, three officials said. CBS News reported that the Israelis played a role in apprehending Mr. Kadish. The Israeli embassy released a one-sentence statement that read: “We were formally informed about the indictment by the relevant U.S. authorities.”

The national director of the Anti-Defamation League, Abraham Foxman, said he was surprised by the arrest of Mr. Kadish. “This is very curious, bizarre, astonishing,” Mr. Foxman said. “If in fact this was an alleged criminal act which went against the security of the United States, why did they wait for 23 years? Why did they wait till the defendant came to the age of 84? It is so strange, astonishing. I don’t understand if this is serious or not serious. If this is serious, why wait 23 years? If it’s not serious, why do it after 23 years?” Mr. Foxman added that if the allegations are true, “then this man should be in jail and he should have been in jail.”

Mr. Foxman said he did not think the arrest would have much impact on America’s relationship with Israel. “After the Pollard case, there were ups and downs, but the relationship was such that Israel made it abundantly clear that it will not engage in any of these activities,” he said, noting that the indictment itself refers to activities between 1979 and 1985. “I don’t think this changes the relationship between the intelligence communities,” which, he said, since 2001 in the fight against terrorism, “has been as close as one can imagine.”

The executive vice chairman of the Conference of Presidents of Major American Jewish Organizations, Malcolm Hoenlein, said: “I don’t anticipate this will have any direct impact on U.S.-Israel relations. We are talking about charges that are more than two decades old and have yet to be substantiated. It will certainly have nothing to do with the ability of the United States to rally allies and others to any cause, especially regarding Iran.”

The linkage to Iran is tricky in some ways, because Iran and the Islamic republic’s supporters in Washington often argue that it is unfair Israel has a nuclear weapon but Iran is not allowed to pursue uranium enrichment. Critics of Iran point to the country’s reliance on terrorism as statecraft and the rhetoric of its political leadership promising to destroy the Jewish state, a parallel that does not exist at the center of Israeli politics.