Lebanon's Shi'ite militant Hezbollah group has dismissed Bulgaria's claim that is was behind last year's bomb attack that killed five Israeli tourists.
Hezbollah Deputy Leader Naim Qassem said the accusations were part of a smear campaign waged by Israel after it failed to defeat the group militarily.
On Tuesday, the Bulgarian government said that two Hezbollah operatives were among the three men responsible for the July 18 bombing of a tour bus at the Black Sea town of Burgas.
Interior Minister Tsvetan Tsvetanov said the men were carrying Canadian and Australian passports and had lived in Lebanon since 2006 and 2010.
The announcement prompted calls by the White House and Israel for measures to hold the militant group accountable.
Some Bulgarian analysts and opposition leaders have criticized the government's allegations against Hezbollah, saying they were unjustified and dangerous.