NEW YORK, April 22: US authorities arrested an American engineer on Tuesday after accusing him of passing secrets on nuclear weapons, fighter planes and air defence missiles to Israel during the 1980s.

Ben-Ami Kadish admitted his spying in FBI interviews and said he acted out of conviction that he was helping Israel, the justice department said. He was charged with reporting to the same Israeli government handler as Jonathan Jay Pollard, who is serving a life term on a 1985 charge of spying for Israel.

Agencies add: The State Department said Washington would express concern to Tel Aviv over the espionage case.

“These kinds of activities whether they occurred long in the past or present time are not the kind of actions we would expect from a friend and ally and we would expect that Israel would not be engaged in such activities,” said spokesman Tom Casey.

“We will be discussing, if we haven’t already, this issue with the Israelis,” he said.

Washington would relay its concerns through the Israeli embassy in Washington, said the official.

Kadish’s arrest is a sign the Pollard scandal may have spread wider than was previously acknowledged. Kadish was arrested in New Jersey and was scheduled to be arraigned on Tuesday afternoon at US District Court in Manhattan, authorities said.

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, and Israel acknowledged in 1998 that the former US Navy intelligence analyst was one of its spies. Pollard has been granted Israeli citizenship.

Kadish is a Connecticut-born US citizen who worked as a mechanical engineer at the US Army’s Armament Research, Development and Engineering Center at the Picatinny Arsenal in Dover, New Jersey.

His spying for Israel lasted roughly from 1979 to 1985, and his contact with the unidentified 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 50-100 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 and Kadish returned them to the library, the complaint said.It said one of the classified documents passed on by Kadish “contained information concerning nuclear weaponry”. Another 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”. It did not identify the country.

A third document contained information regarding the USPatriot missile air defence system.

The complaint said Kadish maintained contact with CC-1, met him in Israel in 2004, and telephone with him on March 20 of this year, after his first FBI interview. It said the handler told him to lie to US 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.