Israeli security apparatuses are on heightened alert ahead of the sixth anniversary of the assassination of Hezbollah terror chief Imad Mughniyeh on Wednesday.

“Hezbollah hasn’t stopped looking [for ways] to avenge the death of Mughniyeh; it’s searching for opportunities,” an unnamed security official told the Walla news website Monday. “Some were prevented. Some almost succeeded. The instructions are to increase alertness.”

Mughniyeh was a key military commander of Hezbollah’s paramilitary and intelligence arms. He was assassinated in 2008, in an operation that is widely believed to have been carried out by Israeli agents. Hezbollah has vowed to retaliate.

In February 2012, on the fourth anniversary of the Hezbollah commander’s death, Israel’s diplomatic missions in New Delhi and Tbilisi were attacked, and analysts connected the offensives with Hezbollah. In May of that year five Israelis were killed in a bus bombing in Burgas, Bulgaria. A Bulgarian investigation later implicated Hezbollah.