Israel had hand in manufacturing pagers that exploded in Lebanon: Source
Dozens of people have been killed in the pager attacks.
Israel had a hand in the manufacturing of pagers that exploded on Hezbollah operatives this week, with this type of "supply chain interdiction" operation having been planned for at least 15 years, a U.S. intelligence source confirmed to ABC News.
The CIA has long been reluctant to employ this tactic because the risk to innocents was too high, the source said.
Planning for the attack involved shell companies, with multiple layers of Israeli intelligence officers and their assets fronting a legitimate company that produced the pagers, the source confirmed to ABC News, with at least some of those doing the work unaware of who they were actually working for.
RELATED: What to know about the 2 waves of deadly explosions that hit Lebanon and Syria
Israel's hand in the manufacturing was first reported by The New York Times.
One to two ounces of explosives and a remote trigger switch to set off the blast were planted in the pagers, according to the sources.
The last two days of explosions in Lebanon, triggered remotely with explosives inside pagers or walkie-talkies, have killed at least 37 people and wounded 2,931, according to Lebanese Health Minister Firass Al-Abyad.
Israel, Hezbollah trade strikes amid exploding device fallout
The conflict between Hezbollah and Israel grew wider on Thursday, with Israel launching strikes on Lebanon and Hezbollah returning fire.
ABC News has reached out to BAC Consulting -- the Hungary-based company contracted to produce the pagers on behalf of Gold Apollo in Taiwan -- but neither company has responded to our repeated requests.
The pagers were never in Hungary and the company was "a trading intermediary, with no manufacturing or operational site in Hungary," a spokesperson for the Hungarian government told ABC News on Wednesday.
In a speech Thursday, Hezbollah leader Hassan Nasrallah said the group's top leadership had old pagers, not the new ones used in the attack, which were reportedly shipped in the last six months. The group has begun a full investigation into the explosions.
"Not all of the pagers had been distributed and some of them were turned off," Nasrallah said.
"Over two days, the enemy wanted to kill at least 5,000 people. ... The enemy knew that the pager devices numbered 4,000," he added.
ABC News' Nasser Atta contributed to this report.
