The mission was created in 1978 to help restore order after Israel's first invasion of Lebanon. Decades later, it's still there but has come under fire during a new Israeli invasion in Lebanon.

The Israeli attack on the Lebanese army came hours after Israeli troops fired on the headquarters of U.N. peacekeepers in southern Lebanon, injuring two peacekeepers for the second time this week.

The Hamas-led assault that killed 1,200 people triggered a devastating Israeli military response in Gaza. Now the war has engulfed Lebanon and threatens to bring Israel and Iran into direct conflict.

The Middle East is bracing for a wider war as Israel fights in Gaza and Lebanon, and promises a strong response to Iran's missile strikes.

Lebanese Prime Minister Najib Mikati said his country was facing “one of the most dangerous phases of its history” amid Israel’s ground incursion into southern Lebanon, which began late Monday.

The Israeli military pressed its ground incursion into southern Lebanon on Tuesday, calling the operations “limited incursions” that are targeting Hezbollah militants.

Israeli commandos are currently conducting a raid inside southern Lebanon, and there are indications that Israel may send more forces into the area, a senior U.S. official told NPR.

The first apparent Israeli airstrike on central Beirut in nearly a year of conflict leveled an apartment building early Monday. It came after Israel hit targets across Lebanon and killed dozens of people.

After Israel killed Hezbollah's leader, the U.S. says it wants to stop Iran from "exploiting the situation or expanding the conflict."

The Israeli military said it carried out an airstrike on the headquarters of Hezbollah in Beirut, shortly after Israeli Prime Minister Benjamin Netanyahu addressed the United Nations.

In a fiery speech at the United Nations General Assembly, the Israeli prime minister said his country would is "winning" and would attack Iran and its proxies anywhere in the Middle East.

With Israel and Hezbollah locked in the fiercest fighting in decades, many Lebanese have taken refuge in schools, hotels and other shelters.

Hezbollah launched a ballistic missile at Tel Aviv early Wednesday, after Israel carried out strikes on Lebanon that killed hundreds of people and the militants fired rockets across northern Israel.

The trade of cross-border missiles came after the deadliest day of conflict in Lebanon since 2006. Lebanon’s health ministry said on Tuesday that 558 people have been killed.

Fighting is escalated at the Israeli-Lebanese border in one of the deadliest days of nearly a year of conflict in the region.