The attack reportedly took place during a meeting between senior Iranian and Hezbollah officials.
The tunnel was operated by Hezbollah’s 4400 Unit, which is responsible for the transportation of weaponry from Iran to Lebanon.
Aziz Salha, photographed preparator of Ramallah lynching, killed in IAF strike in Gaza • Funeral of Hezbollah leader Nasrallah on Friday • Hamas refused to take part in negotiations for several weeks
Hassan Jafar Kasir's reported assassination is another severe blow to Hezbollah as its leadership has been slowly picked off in Israeli operations.
Syrian state television earlier said that one of its presenters was killed in an Israeli strike on Damascus.
Since 2006 and the Second Lebanon War, the quality and extent of intelligence Israel was able to gather on the terror group changed significantly.
Syrians in the country’s last rebel holdout celebrated the Hezbollah chief’s assassination and shared hopes that Bashar Assad would be killed as well.
Hezbollah leader Nasrallah found dead after IAF strike in Beirut, along with 20 Hezbollah terrorists, including senior commanders.
Former PM Ehud Olmert confirms Israel's role in the 2008 killing of Hezbollah's Mughniyeh, breaking 16-year silence on covert Syria mission.
The military targeted a mid-level senior Hezbollah official in the area, Army Radio reported.