The recent detention of a retired telecoms expert on suspicion of spying for Israel's Mossad intelligence agency for 35 years has stunned Lebanon, where 150 foreign agents have been arrested since 2009.

This roundup included several army generals and colonels, politicians, businessmen as well as humbler folk, Christian and Muslim alike, exposing just how extensively the Mossad, and probably other Israeli spy services, allegedly penetrated every level of Lebanese society over the years.

Lebanese Justice Minister Ibrahim Najjar recently drew up a list of 150 cases to be filed as a complaint against Israel to the U.N. Security Council.

The findings, he told the London's Arabic daily Al-Hayat, "are hard to believe."

Judicial and security officials gave few details as the suspect, identified as Elias Younes, underwent interrogation. But Lebanon's official news agency reported he was a longtime employee of the state-run Ogero telecommunications company.

Al-Manar, the television network run by Hezbollah, the Iranian-backed Shiite movement that's the primary target of Israel's intensive espionage operation in Lebanon, alleged that Younes supplied Mossad with voluminous intelligence over the decades.

It said this involved technical data, including military and naval communications and movements, as well as detailed information on Lebanese officials, no doubt many of them Hezbollah members.

The network said Younes confessed he was recruited by Mossad in 1977. Many suspects, including several key telecommunications officials, were recruited in the 1980s and '90s.

That makes Younes the longest-serving of the alleged Israeli agents who have been rounded up over the last three years in a counterintelligence operation that's probably one of the most successful in modern history, certainly in the conflict-plagued Middle East where espionage is endemic.

"Wherever you dig in Lebanon you find a spy," political science Professor Hilal Khashan of the American University of Beirut was quoted as saying by The Media Line, a regional news portal.

He said the crackdown on Israeli espionage cells was largely due to a politically inspired contest between Military Intelligence, increasingly taken over by Hezbollah which controls the current Beirut government, and the intelligence branch of the Sunni-dominated Internal Security Forces.

There seems little doubt that Hezbollah is using the seemingly endless flow of broken spy cells as anti-Israel propaganda to make political capital to burnish its nationalist credentials.

The movement's many critics suggest this is intended to deflect the potential damage it faces over the indictment of four of its members, two of them senior security officials, for the 2005 assassination of Lebanese statesman Rafik Hariri in a massive bombing in Beirut.

The indictments were handed down by the United Nations-backed Special Tribunal for Lebanon, established to investigate the Hariri assassination and to put suspects on trial at a special court in The Hague.

Hezbollah, which is also backed by Syria, denies having anything to do with the assassination of Hariri, a key pro-Western Sunni leader and five-time prime minister. It refuses to hand over the suspects and has threatened to "cut off the hands" of anyone who tries to apprehend them.

Hezbollah, whose own intelligence apparatus is highly rated by its opponents, hasn't indicated how deeply Mossad may have penetrated its ranks.

None of its members have been arrested for spying, although last June Hezbollah admitted it had apprehended three it said worked for the CIA or Israel at a "low level."

Among the score of suspects who've been convicted of spying for Israel is former army Brig. Gen. Fayez Karam, a senior member of the Free Patriotic Movement, a Maronite Catholic party headed by former army commander Gen. Michel Aoun.

Aoun is a vital political ally of Hezbollah and presumably has some degree of access to the secretive Shiite group's inner leadership. Many Christians consider him a traitor for his controversial alliance.

Karam was commander of the army's counterespionage unit during the 1980s and has been close to Aoun for decades. Arrested in August 2010, he was the first prominent political figure to be held on espionage charges.

Karam faced a possible death sentence but last September was sentenced to three years' hard labor by a military tribunal. This was later cut to two years amid widespread suspicions of a political fix. Six other suspects have been condemned to death.