Matthew Levitt analyzes the recent history of Hezbollah's external operations, which were revived after the Israeli assassination of Imad Mughniyeh, the terror leader who was behind multiple anti-American and anti-Israeli attacks:

Mughniyeh's assassination led to the resurrection of Hezbollah's international operations arm, which Hezbollah leaders actively paired down in the wake of the 9/11 attacks in an effort to keep the group out of the crosshairs of the "global war on terror." The drawdown helps explain why Hezbollah's Islamic Jihad Organization experienced so many failures when it first set out to avenge Mughniyeh's death. Not only was the terrorist mastermind Mughniyeh no longer there to quarterback operations, but the group lacked the resources and capability to carry out a successful operation abroad. In light of the far tighter security environment now in place in the Western world since 9/11,

Hezbollah has also generally shied away from trying to carry out attacks in the West, opting instead to operate in places where security is still relatively lax and where the group has cells and supporters (of its own or belonging to its Iranian patron). Thus, attacks in places like Baku, Bangkok, and now Burgas. In Bulgaria, Hezbollah may have relied on Lebanese drug and other criminal organizations that have long provided funds to the group. A 2008 Bulgarian government commission concluded that profits from drug trafficking through the country supports Hezbollah and other militant groups. This was likely on the agenda when then Mossad chief Meir Dagan paid an official visit to Sofia in 2010 to meet with the Bulgarian Prime Minister.