Thousands of Iranians attended a funeral procession in Tehran on Tuesday for two Revolutionary Guards killed in Israeli strikes in Syria last week.
Israel launched several missiles on Friday from the occupied Golan Heights against positions near Damascus, part of a series of attacks over recent days including early Tuesday.
"The Zionists are trying to target the resistance front, but the resistance will become stronger and more motivated," said Iranian Revolutionary Guard Corps spokesman Ramazan Sharif, according to the Tasnim News Agency.
"We will avenge the blood of martyrs Milad Heidari and Meghdad Mahghani," he vowed, while thousands gathered in central Tehran to mourn them, chanting "down with Israel".
"Follow their path," Heidari's mother told the large crowd at the funeral, urging them to ensure the victims' blood was not spilled in vain.
During more than a decade of civil war in Syria, Israel has launched hundreds of air strikes on its territory, targeting Iran-backed forces and Lebanese Hezbollah fighters as well as Syrian army positions.
Iran, a key ally of Syrian President Bashar al-Assad, says it only deploys military advisers in the conflict-ravaged country.
Iran's foreign ministry spokesman, Nasser Kanani, accused arch enemy Israel of bringing "war and insecurity" to the Middle East and of "creating discord in the region".
In an apparent reference to Israel's recent political turmoil and mass protests against the hard-right government's proposed judicial reforms, he charged that there will be "no escape from internal collapse".