What to know as Israel says troops are entering Lebanon for ground operations against Hezbollah

Almost a year after Israel launched its war against Hamas in the Gaza Strip in retaliation for the Iran-backed group's Oct. 7 terrorist rampage, it announced the beginning of what the Israel Defense Forces said would be "limited, localized, and targeted ground raids" against Iran's much larger, better-armed proxy group Hezbollah in Lebanon. The ground operations were announced after about two weeks of blistering airstrikes on Hezbollah strongholds in southern Lebanon and the southern suburbs of Lebanon's capital, Beirut, which have killed more than 1,000 people and displaced about 1 million people from their homes, according to Lebanese officials.

The aerial assault — and unprecedented covert operations before it that saw thousands of pagers and walkie-talkies held by Hezbollah militants blown up with embedded explosives — largely decapitated the U.S.-designated terrorist organization. Its longtime leader Hassan Nasrallah was killed in an airstrike on Sept. 27, and at least half a dozen other senior figures, and dozens of mid-level operatives, have also been killed. But even as Israel prepared to launch its ground operation, Hezbollah's surviving deputy leader said the group was ready for war.

Below is a look at how the arch enemies came to be at war again for the first time since a roughly one-month conflict in 2006 that left more than 1,000 people dead in Lebanon and more than 150 in Israel — and what's at stake this time amid fear that Iran and the U.S. could be drawn into the fighting.