Justin Salhani: Israel says it launched a preemptive attack on positions in Lebanon from which Hezbollah was preparing to attack Israel.

Hezbollah launched its own attack on Israel later on Sunday morning, targeting several military and intelligence targets.

Hezbollah Secretary-General Hassan Nasrallah said the operation was ordered after Israel crossed all “red lines” in attacking Beirut’s southern suburbs and killing Hezbollah commander Fuad Shukr at the end of July.

The two sides have been trading tit-for-tat attacks since October 8, the day after Israel launched its war on Gaza following Hamas-led attacks on southern Israel. Hezbollah began engaging Israel in small attacks across the Lebanon-Israel border, saying it would stop only when Israel halted its war.

Al Jazeera spoke to experts to get answers to five questions about Sunday’s exchange of attacks.