U.S. authorities arrested an American engineer on Tuesday on suspicion of giving secrets on nuclear weapons, fighter jets and air defence missiles to Israel during the 1980s, the Justice Department said.

Ben-Ami Kadish, 84, acknowledged his spying in FBI interviews and said he acted out of a belief that he was helping Israel, court papers said. He was accused of reporting to an Israeli government handler who also dealt with Jonathan Jay Pollard, an American citizen serving a life term on a 1985 charge of spying for Israel.

Kadish's arrest is a sign the Pollard scandal, which remains an irritant in the close U.S. alliance with Israel, may have spread wider than was previously acknowledged.

Kadish was arrested in New Jersey and was scheduled to be arraigned on Tuesday afternoon at U.S. District Court in New York City, authorities said. "We will be informing the Israelis of this action," State Department spokesman Tom Casey said.

"Twenty-plus years ago during the Pollard case we noted that this was not the kind of behaviour we would expect from friends and allies and that would remain the case today." Kadish's lawyer, Bruce Goldstein, did not immediately return a call for comment.

Israeli Foreign Ministry spokesman Arye Mekel, asked about the arrest, said: "We know nothing about it. We heard it from the media." Pollard pleaded guilty in 1986. Israel granted him citizenship in 1996 and acknowledged in 1998 that the former U.S. Navy intelligence analyst was one of its spies.

Israel has unsuccessfully sought Pollard's release.

Kadish is a Connecticut-born U.S. citizen who worked as a mechanical engineer at the U.S. Army's Armament Research, Development and Engineering Center at the Picatinny Arsenal in Dover, New Jersey. His spying lasted roughly from 1979 to 1985, and his contact with the unnamed Israeli handler continued until March of this year, the federal complaint against him said.

The complaint said Kadish did not appear to receive any money in exchange for his suspected spying, just small gifts and restaurant meals. Kadish, who had a security clearance, took 50 to 100 classified documents from the arsenal's library, working from a list provided by the handler identified in a federal complaint as "CC-1."

The handler would then photograph the documents in Kadish's basement and Kadish would return them to the library, the complaint said.

It said one of the classified documents passed on by Kadish "contained information concerning nuclear weaponry." Israel is widely believed to have nuclear weapons but has never acknowledged it.

Another document obtained by Kadish related to "a major weapons system ... a modified version of an F-15 fighter jet that the United States had sold to another foreign country," the complaint said. It did not identify the country.

A third document contained information regarding the U.S. Patriot missile air defense system. The complaint said Kadish maintained contact with CC-1, met him in Israel in 2004, and spoke with him by telephone on March 20 of this year, after his first FBI interview.

It said the handler told him to lie to U.S. authorities: "Don't say anything ... What happened 25 years ago? You don't remember anything," the handler was quoted as saying. The complaint said the handler worked for the Israeli government as consul for science affairs at the Israeli Consulate General in New York, from 1980 to November 1985. During the late 1970s the handler worked for what was known at the time as Israeli Aircraft Industries, an Israeli government contractor, the complaint said. It said the handler left the United States when Pollard was arrested and has not returned.

The history appears to fit with that of Yosef Yagur, who has been publicly linked to the Pollard case. A woman who identified herself as Yagur's wife, when reached by telephone, said, "We're not speaking to journalists. Goodbye."

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