Hezbollah -
The Iran-backed Lebanese group has an arsenal of an estimated 130,000 rockets and missiles,
all pointed at Israel.
https://www.bbc.com/news/world-middle-east-68724691Hezbollah is one of the most heavily armed, non-state military forces in the world - independent estimates suggest the group has between 20,000 and 50,000 fighters, and many are well-trained and battle-hardened through their participation in the Syrian civil war.
The Iran-backed Lebanese group has an arsenal of an estimated 130,000 rockets and missiles, according to the Center for Strategic and International Studies think-tank.
Yet the experts the BBC spoke to thought it unlikely that the group would launch a major escalation against Israel.
"Hezbollah does not really want to fall into Israel's trap because they realise Benjamin Netanyahu and his war cabinet are desperately trying to expand the war," said Mr Gerges.
"The political future of Benjamin Netanyahu depends on the continuation of the war in Gaza and its escalation into northern fronts with Hezbollah and even with Iran itself."
A 'symbolic' reaction?
Mr Sadrzadeh believes Iran is likely to show a "symbolic" reaction rather than risking a direct war with Israel.
"Iran is an expert in carrying out symbolic attacks like the one in response to the killing of its most important military commander Qasem Soleimani," Sadrzadeh said, referring to a ballistic missile attack by Iran against an Iraqi air base where US troops were stationed - a week after the US assassinated the Iranian general in Baghdad.
Despite Iran's promise of "severe revenge", no US military personnel stationed at the base were killed, and there were reports that the US military had been warned in advance of the incoming missiles.