Israel's Shin Bet security agency said Tuesday that it has broken up an Iranian plot to recruit Israelis of Iranian origin as spies, part of what it says is a burgeoning Iranian intelligence operation against the Jewish state.

The affair highlights a quirk in the hostile relations between the countries — Iranian President Mahmoud Ahmadinejad repeatedly calls for Israel's destruction but allows Israeli Jews with relatives in Iran to visit his country.

Israeli security officials told reporters that Shin Bet agents detained an Israeli returning from a visit to relatives among Iran's 25,000-member Jewish community. He told interrogators he was given money by Iranian intelligence operatives and asked to help them spy on Israel.

Shin Bet briefing documents obtained by The Associated Press did not specify when the man was picked up, if he carried out the request or if he was released after questioning, but Israeli media reports said no charges had been brought.

The documents said it was just one of several such cases.

"Over the past year Iranian intelligence has increased its activity against Israel," the papers said. "The Shin Bet has recently uncovered a number of attempts by Iranian intelligence to recruit Jews, Israeli citizens of Iranian descent, who went on family visits to Iran."

No specific number was given, but Israel Army Radio cited an unidentified senior Shin Bet officer as saying the agency uncovered 10 recruitment attempts in the past two years.

There was no comment from the Iranian government.

According to Israeli government figures, about 135,000 Israeli Jews trace their roots to Iran, which had good relations with Israel before Ayatollah Ruhollah Khomeini's 1979 Islamic Revolution.

Army Radio said about 100 Israelis had visited family members in Iran over the past two years.

The Israeli documents said Iranian intelligence seized upon that fact as an opportunity to press Israeli-Iranians into espionage.

The documents said most of the recent Iranian recruitment attempts began at Iran's consulate in Istanbul, Turkey. The papers said at least two people at the consulate were intelligence officers working under diplomatic cover, identifying them only as "Abdalahi" and "Zinali."

Turkey is a short flight from Tel Aviv and a convenient point for Israelis of Iranian origin seeking to obtain an Iranian passport so they can visit their relatives. Iran does not have diplomatic relations with Israel and does not allow entry on an Israeli passport.

Citing the Shin Bet officer, Army Radio said Iranian officials at the Istanbul consulate quizzed passport applicants about their Israeli military service and about the general economic and security climate in Israel.

Reserve Col. Shimon Buyavsky, former head of the Iran- Iraq section in Israeli military intelligence, said it was possible Shin Bet revealed its findings in order to pressure Israeli civilian authorities to ban such visits.

"I think the aim in making this public is to show Israelis the danger involved, to get the establishment to act against it and to tell the Iranians we know what they're up to," he told Army Radio.

An Israeli who was born in Tehran, Avi Igai, told the radio he was issued an Iranian passport in Istanbul and visited Iran's capital for a family wedding last September. He said he was not questioned, or asked to spy, either at the consulate or on entry to Iran.

"I went there for my niece's wedding and to visit my father's grave," he said, adding that he would consider going again as long as it was not against any law.

Buyavsky said people like Igai were tempting targets for an Iranian sting operation.

"Next time, if he goes back, he may find that his niece who got married is now a hostage, and they can put her in prison if he does not start passing information from Israel," Buyavsky said. "That's how it starts."