Hezbollah denounced Israel on Wednesday for waging an "international campaign" against it after Bulgaria said the Lebanese Shiite militant movement was behind a July bombing that killed five Israeli tourists.
Naim Kassem, the group's number two, slammed the "international campaign of intimidation waged by Israel against Hezbollah," and said it is "ever improving its equipment and training" and that "these charges will change nothing."
Kassem did not make specific reference to the bombing that also killed one Bulgarian, in his first comments since the accusation was made by Sofia on Tuesday.
In remarks published by Lebanon's National News Agency, Kassem said "there is a global attack led by Israel to confront the resistance in Lebanon and Palestine... targeting Hezbollah specifically because (Israeli) aggression has failed against Hezbollah.
"Today the world is divided between the resistance and those who seek international hegemony, and we know that the resistance can triumph."
The Bulgarian government said two people using Canadian and Australian passports linked to Hezbollah were behind the July 18 bombing of a bus at the Black Sea Burgas airport.
After the announcement, the White House and Israel called on Europe to take action against Hezbollah.
US President Barack Obama's top counter-terrorism adviser John Brennan, his nominee to head the CIA, urged European states to take "pro-active action" to uncover Hezbollah's infrastructure, financing and operational networks.
Israeli Prime Minister Benjamin Netanyahu said the Bulgarian finding that Hezbollah was behind the bombing should push the EU to draw the "necessary conclusions" about the group, hinting it should be placed on a terror watch list.
Hezbollah is the most powerful faction in the Lebanese cabinet, and its militia is also the country's most powerful military force.