A Hezbollah commander, two other fighters and seven civilians were killed in an Israeli strike in south Lebanon's Nabatiyeh, a security source said Thursday, raising the toll from a raid a day earlier.

The deaths brought to 10 the total number of civilians killed in Israeli strikes on Wednesday, the highest such toll since cross-border hostilities began in October, further raising fears of a broader conflict between Israel and militant group Hezbollah.

The U.N. peacekeeping force deployed along the Lebanon-Israel border, known as UNIFIL, expressed concerns Thursday over the latest “exchanges of fire,” and urged all sides involved to halt hostilities to prevent further escalation.

“Attacks targeting civilians are violations of international law and constitute war crimes,” UNIFIL’s spokesman Andrea Tenenti said in a statement. “The devastation, loss of life, and injuries witnessed are deeply concerning.”

Senior Hezbollah official Sheikh Nabil Qaouq said Thursday at an event in south Lebanon that his group is “prepared for the possibility of expanding the war” with Israel, a day after the fiercest escalation since the beginning of clashes.

Hussein Berjawi had invited his daughter, her husband and their two young sons to dinner in south Lebanon, but an Israeli strike nearly wiped them all out.

At least five family members -- Hussein Barjawi, his daughters Amani and Zeinab, his sister Fatima and Zeinab's son Mahmoud Amer -- were killed in the strike on the city of Nabatiyeh.

Kataeb Party leader MP Sami Gemayel on Thursday stressed that “all the Israeli excuses for targeting civilians are rejected and condemned,” hours after ten Lebanese civilians were killed in Israeli airstrikes across south Lebanon.

Former Progressive Socialist Party leader ex-MP Walid Jumblat on Thursday said that the proper implementation of U.N. Security Council Resolution 1701 (2006) would prevent “further escalation” between Israel and Hezbollah.

Caretaker Prime Minister Najib Mikati condemned Thursday the escalation as more Israeli strikes were reported in south Lebanon.

"At a time where we are insisting on calm and call all sides to not escalate, we find the Israeli enemy extending its aggression," read a statement from Mikati's office.

Israeli warplanes carried out Thursday several airstrikes on Wadi Slouqi in south Lebanon as the civilian death toll from Wednesday's airstrikes rose to 10.

Israel's air force also struck the border towns of Labbouneh, Majdal Selm, Maroun al-Rass, Blida and Houla. The Israeli military said Thursday's strikes targeted Hezbollah infrastructure and launch posts.

At least 10 people, mostly civilians, were killed on Wednesday in Israeli strikes on south Lebanon, while the Israeli army said it lost a soldier in cross-border rocket fire.

While the rocket attack was not immediately claimed, the exchanges of fire -- and the worst single-day civilian death toll in Lebanon since cross-border hostilities began in October -- raised fears of a broader conflict between Israel and Hezbollah.

The slow-simmering cross-border conflict between Lebanon's Hezbollah and Israeli forces escalated Wednesday, reviving fears that the daily clashes could expand into an all-out war.

A rocket fired from Lebanon struck the northern Israeli town of Safed, killing a 20-year-old female soldier and wounding at least eight people.