JERUSALEM/BEIRUT, March 16 (Xinhua) -- Israeli forces launched ground operations on Monday against Hezbollah strongholds in southern Lebanon, the Israel Defense Forces (IDF) said, opening a new front in a widening regional conflict.

Defense Minister Israel Katz said the operation aimed "to remove threats and protect the residents of the north." He added that hundreds of thousands of southern Lebanese residents evacuating homes south of the Litani River would not be allowed to return until northern Israeli communities were secured.

"Prime Minister Netanyahu and I have instructed the IDF to destroy the terror infrastructure in the Lebanese border villages, just as it was done against Hamas in Rafah, Beit Hanoun, and the terror tunnels in Gaza," Katz said, warning that Israel could target Hezbollah Secretary-General Naim Qassem.

Israeli troops, supported by Merkava tanks and armored personnel carriers, advanced at dawn toward the towns of Khiam and Aitaroun and surrounding villages. The incursion was backed by airstrikes, artillery, drones, and warplane attacks, according to security sources.

The heaviest fighting was in the eastern sector, where Israeli forces moved from Tal al-Hamamis toward Khiam, a longstanding flashpoint. In the central sector, troops advanced toward Aitaroun, Yaroun, and Bint Jbeil, aiming to seize high ground above Wadi al-Hujeir. In the west, forces targeted the villages of al-Dhahira and Alma al-Shaab before pulling back to Labbouneh heights under Hezbollah missile and artillery fire.

Hezbollah said its fighters repelled Israeli advances throughout the day, striking a Merkava tank north of the Khiam detention center with a guided missile and hitting an Israeli troop gathering near the Kfar Yuval settlement with rockets.

Fierce resistance blocked Israeli forces from entering Khiam and advancing along the Taybeh axis, sources said, adding that Israeli forces have established positions at roughly 15 border points, advancing one to three kilometers north of the Blue Line, the UN-demarcated boundary between Israel and Lebanon.

Eyewitnesses reported heavy shelling, machine-gun fire, and airstrikes across dozens of localities during the night and early morning.

The ground operation escalates a conflict that began on Feb. 28 with a U.S.-Israeli air campaign targeting Iranian facilities. Hezbollah, an Iranian ally that controls much of southern Lebanon, resumed attacks on March 2, two days after the killing of former Iranian Supreme Leader Ali Khamenei in a U.S.-Israeli strike.

Monday's clashes were among the fiercest since a ceasefire ended a year-long war in late 2024, which had displaced hundreds of thousands of people and caused widespread infrastructure damage on both sides.