The threat comes as Israel launches a ground incursion against the Iran-backed militant group Hezbollah in southern Lebanon.
Iran's leadership has vowed revenge, but its actions and language suggest — at least so far — a more measured response.
Hezbollah’s acting leader vowed Monday to keep battling Israel and said the Lebanese militant group was prepared for a long ...
Israel has plunged Hezbollah into disarray and decapitated its leadership. How Iran will react is an open question.
Israel has killed many of Hezbollah's senior leaders with devastating strikes in Lebanon, but neither side appears ready to ...
An airstrike has leveled an apartment building and killed three Palestinian militants in central Beirut, as Israel appeared ...
Follow NBC News' live coverage as Iran responds to Hezbollah leader Hassan Nasrallah's killing in an Israeli strike.
Hezbollah is entirely a creature of Tehran, unlike Hamas and the Houthis, which, though backed by Iran, were not founded ...