The trial over a deadly 2012 bombing of Israeli tourists in Bulgaria, due to start on Monday, has been pushed back to November because of a procedural error, prosecutors said.
The opening was delayed because the Sofia court had failed to inform the victims' families of the start date, prosecutors told AFP.
The proceedings against two alleged suspects in the attack, who are on the run and being tried in absentia, will now start on November 10.
A Franco-Lebanese national, identified as Mohamad Hassan El-Husseini, blew up a bus carrying Israeli tourists at the airport of the Black Sea coast resort of Burgas on July 18, 2012.
Five Israelis, their Bulgarian driver and the bomber himself died in the attack, which left 35 other Israelis injured.
Bulgarian authorities identified the attacker's alleged accomplices as two Lebanese men with links to the Lebanese militant group Hezbollah, named as Australian passport holder Meliad Farah and Canadian citizen Hassan El Hajj Hassan.
The attack -- which both Israel and Bulgaria blamed on Hezbollah -- was the deadliest hit against Israelis abroad since 2004.
It played a role in a subsequent European Union decision to blacklist Hezbollah's military wing as a terrorist organisation.