Factbox-In Lebanon, UN peacekeepers are caught in the firing line

BEIRUT, March 31 (Reuters) - Three U.N. peacekeepers were killed this week in southern Lebanon, making the latest war between Israel and Hezbollah one of the deadliest chapters for a peacekeeping mission whose decades-long mandate expires this year.

The U.N. Interim Force in Lebanon (UNIFIL) first deployed in 1978 and has remained through successive conflicts, including a 2024 war during which its positions came under fire repeatedly.

In line with a Security Council decision, UNIFIL will cease operations at the end of 2026 and withdraw in 2027. As of March, UNIFIL had 7,505 peacekeepers from 47 nations.

HOW WERE THE PEACEKEEPERS KILLED?

The three peacekeepers, all from Indonesia, were killed in two separate incidents.

Initial findings in a probe into the deaths of two of them point to a roadside explosion striking their convoy near Bani Hayyan on Monday, the head of U.N. peacekeeping said.

Israel's ambassador to the U.N. said that Hezbollah explosive devices hit the peacekeepers in that incident. UNIFIL spokesperson Kandice Ardiel invited Israel "to share their evidence with our investigative team".

Hezbollah didn't immediately respond to a request for comment.

The third peacekeeper was killed when a projectile hit a UNIFIL base near the village of Adchit al-Qusayr on Sunday.

That incident is also being investigated.

UNIFIL positions were struck repeatedly during a war between Hezbollah and Israel in 2024, but no peacekeepers were killed.

Ardiel said "a great deal of violence" was happening near UNIFIL positions: "There are projectiles being launched back and forth between the Israel Defense Forces and non-state actors, presumably Hezbollah."

The last time a U.N. peacekeeper was killed was in 2022, when an Irish peacekeeper died when the vehicle he was in was shot at in south Lebanon. A Lebanese military tribunal sentenced six Hezbollah members over the killing.

WHAT IS UNIFIL'S MISSION?

UNIFIL was set up in 1978 after Israel had invaded Lebanon to counter Palestinian militants in the south. UNIFIL's mission included confirming Israel's withdrawal and helping to restore Lebanon's authority in the area.

While the threat posed to Israel by Palestinian groups diminished, Hezbollah emerged as a new actor hostile to Israel after its 1982 invasion of Lebanon.

After a 2006 war, UNIFIL's mandate was expanded under U.N. Resolution 1701 to include monitoring a ceasefire, supporting the Lebanese army in its deployment into the south, and helping it enforce a prohibition of illegal arms there.

UNIFIL's mission is to monitor the situation and report on violations of Resolution 1701, Ardiel said, adding: "The active conflict has changed what we're able to do as we're no longer able to go out and patrol."

While Israel asked peacekeepers to leave their positions in 2024, it had not done so this time, she said. "But of course, they continue to reiterate that they consider this a dangerous situation" and that peacekeepers "should stay out of the way".

The Israeli military said it is coordinating with UNIFIL and that it had called on "different uninvolved forces and civilians to get out of harm's way" after Hezbollah opened fire.

WHY IS UNIFIL'S MISSION ENDING?

The power balance in Lebanon was turned on its head by the 2024 war, with Hezbollah badly weakened and a new Lebanese government taking office and launching an effort to disarm the group peacefully, beginning in the south.

Citing a "radically different" security environment in Lebanon, the U.S. ambassador to the U.N. agreed to a French-drafted resolution in August extending UNIFIL's mission "for a final time". The Israeli ambassador to the U.N. said at the time that UNIFIL had "failed in its mission and allowed Hezbollah to become a dangerous regional threat".

One Israeli goal in the current war is to establish and maintain security control over the area between the border and the Litani River - the UNIFIL area of operations.

(Reporting by Maya Gebeily in Beirut, Steven Scheer and Emily Rose in Jerusalem, David Brunnstrom in New York; Writing by Tom PerryEditing by Keith Weir)