(CBS News) Seven people were killed Wednesday and dozens injured when a.
Israeli Defense Minister Ehud Barak said Thursday the Iranian-backed Lebanese group Hezbollah carried out the terrorist attack.
What we saw Wednesday in Bulgaria is part of the escalating tensions between Iran, Israel and the West.
A former Iranian agent from that country's feared Revolutionary Guard corps - a man who's been on the inside - tells CBS News that a surrogate, stealth war, carried out in the shadows by both sides, has been going on for more than a year.
It began with the targeted killings of Iranian scientists working on that country's nuclear program.
Then a computer virus was covertly deployed against Iranian nuclear sites. The virus was designed to make the sites self-destruct. Iran publicly accused the U.S., Great Britain and Israel of being behind the plots.
And now, it appears Iran is striking back.
"They're looking at this saying, 'We've got to respond. Aggression has been taken against us,"' says former CIA analyst Phil Mudd. "So that's the first factor. The second factor is, in the background, they're hearing the drumbeats of war."
That drumbeat is the continued discussion over if or when Israel might launch airstrikes against more than a dozen underground suspected Iranian nuclear sites.
But Iran hasn't backed away.
Since the killing of the last Iranian scientist, Iran has been linked to a series of plots:
-- A bomb attached to the car driven by the wife of an Israeli diplomat in India
-- A plan to use local organized crime hit men in a sniper attack in the U.S., and Israeli targets in Azerbaijan and the nation of Georgia
-- A plot using a Mexican drug cartel to kill the Saudi ambassador in a crowded restaurant in Washington, D.C.
-- And just days ago, in Kenya a suspected plot to attack a synagogue in Nairobi and Israeli-owned hotels in the coastal city of Mombasa
The two suspected Iranian agents captured in Kenya on July 3 are believed to be members of Iran's elite Revolutionary Guard force.
Reza Kahlili was once a member of that force himself and for years, he says, a double agent who supplied information to the CIA.
He says these attacks are Iran's version of a warm-up, in the event of a full conflict with Israel.
"They're just sending signals that they are capable of, and the order is by Ayatollah Khamenei, the Iranian supreme leader that, should war break out, then all terror cells will become activated and attack major interests of America, Israel, European countries and even within America," warns Kahlili, author of "A Time to Betray."
But, given the number of alleged plots by Iran against Israeli targets, some analysts wonder why Iran would seem to keep provoking the very attack they say they want to avoid.
"The mindset of this organization that is the Iranian intelligence service and this government is not a Western mindset," Mudd observes. "We see stability as a goal. They see instability and revolution as a goal."
Kahlili says, in the event of an Israeli airstrike, Iran is prepared to up the ante, not by responding militarily, but with a global campaign of terror attacks.
"Should it become an all-out war, then they will definitely respond on the world stage by terrorist attacks within the U.S., in Europe, and against America's interests, against Israel's interests," Kahlili says.
Intelligence officers believe Iran has already done the pre-operation surveillance for a series of terrorist attacks.
There's plenty of evidence that Tehran has scoped out targets, taken photos and written plans for terrorist strikes in the Mideast, Europe, South America, and even the United States.
To see John Miller's report, click on the video in the player above.