The operation follows intense air strikes that have devastated the group's leadership, including assassinating its chief Hassan Nasrallah in Beirut on Friday.
The Israeli military said the operations in Lebanon began on Monday night and involved the elite 98th division, which was deployed to the northern front two weeks ago from Gaza where it had been fighting against Hamas for months.
A missile fired by Hezbollah at Israel fell directly in Kfar Qassem, an Arab village in central Israel, after Hezbollah once again fired projectiles at central Israel.— Israel Defense Forces (@IDF) Hezbollah doesn't care who, or how. They only care about harming Israelis. pic.twitter.com/VHIRdFX3b7October 1, 2024
It said its air force and artillery supported ground troops engaged in "limited, localised, and targeted ground raids" against Hezbollah in southern Lebanon villages that posed "an immediate threat to Israeli communities in northern Israel".
Israel's ground raids will target Hezbollah strongholds along the border that threaten Israel, not a war against the Lebanese people, Israel's military said on Tuesday.
"Hezbollah turned Lebanese villages next to Israeli villages into military bases ready for an attack on Israel," military spokesperson Rear Admiral Daniel Hagari said.
Residents in southern Lebanon fled on Monday and Tuesday as Israeli strikes drew nearer, local sources told Reuters.
Lebanon is facing one of the most dangerous stages in its history, caretaker Prime Minister Najib Mikati said on Tuesday during a meeting with UN organisations and ambassadors of donor countries, in which they made a joint appeal for more than $US400 million ($A579 million) in aid to cope with surging hostilities.
Two Lebanese security sources told Reuters that Israeli units had crossed into Lebanon overnight for reconnaissance and probing operations.
Lebanese troops also pulled back from positions along the border, the source said.
Lebanon's health ministry says at least 95 people have been killed in 24 hours. (AP PHOTO)
Hezbollah said on Tuesday it had launched rocket and artillery attacks against Israeli troops at positions within Israel and made no mention of Israeli forces within Lebanon.
The Israeli military issued a warning to citizens not to move in their vehicles from the area north of the Litani River in Lebanon to its south.
Israel has indicated it is primed for a full-fledged invasion of Lebanon with the stated aim of enabling thousands of its citizens who fled Hezbollah rockets to safely return to their communities near the northern border.
Israel's strikes have displaced one million Lebanese from their homes and killed more than 1100 people, Lebanese authorities have said.
Iran's allies - from Hezbollah to Yemen's Houthis to armed groups in Iraq - have weighed in with attacks in the region in support of Hamas in the Gaza war, raising fears the conflict will engulf the Middle East and suck in the US and Tehran.
Yemen's Houthi movement targeted Israeli military posts in Tel Aviv and Eilat with drones on Tuesday, the group's military spokesperson Yahya Saree said in a televised speech.
An Israeli strike in Lebanon on Tuesday targeted Mounir Maqdah, commander of the Lebanese branch of the Palestinian Fatah movement's military wing, according to Palestinian security officials.
His fate was unknown.
Israel's ground invasion of Lebanon represents an escalation of the conflict in the Middle East. (AP PHOTO)
Israel has not commented on the strike, which hit a building in the crowded Ain al-Hilweh Palestinian refugee camp near the southern city of Sidon, the sources said.
In Syria, three civilians were killed and nine others injured in an Israeli air strike on the capital Damascus, Syrian state media said on Tuesday.
Israel has been carrying out strikes against Iran-linked targets in Syria for years but has ramped up raids since the Palestinian militant group Hamas attacked Israel's southern territory on October 7, 2023.
Hamas killed 1200 people and took about 250 hostages in its assault on Israel, according to Israeli tallies.
Israel in response launched a massive assault on Hamas in Gaza, killing more than 41,300 Palestinians, according to the Gaza health ministry.
Israel's operations in Lebanon follow its deadly detonation of booby-trapped Hezbollah pagers, two weeks of air strikes, and its killing on Friday of Nasrallah.
Overnight, a series of strikes hit Beirut's southern suburbs after the Israeli military warned residents to evacuate areas near buildings it said contained Hezbollah infrastructure south of the capital.
In the past 24 hours, at least 95 people had been killed and 172 wounded in Israeli strikes on Lebanon's southern regions, the eastern Bekaa Valley, and Beirut, Lebanon's health ministry said early on Tuesday.
9°C