Two Indonesian peacekeepers were killed on Monday by a roadside explosion in southern Lebanon, UN peacekeeping chief Jean-Pierre Lacroix has said, citing the findings of an initial investigation.

In a separate statement, the United Nations Interim Force in Lebanon (Unifil) said the explosion was of unknown origin and destroyed the peacekeepers' vehicle near Bani Hayyan.

A third peacekeeper was severely injured in the explosion, and a fourth was hurt, Unifil said.

This incident is the second fatal incident in 24 hours. Another peacekeeper - who was also Indonesian - was killed on Sunday when a projectile, also of unknown origin, exploded in Adchit Al Qusayr, southern Lebanon.

Unifil said it had launched investigations to determine what happened in both incidents.

The findings of an initial investigation into the incident on Monday point to a roadside explosion striking the convoy, Lacroix told the UN Security Council earlier.

Their deaths had most likely been caused by an IED (improvised explosive device), Stéphane Dujarric, spokesperson for the UN secretary-general, later said at a briefing.

Speaking about the other incident, on Sunday, Dujarric said it was likely caused by an explosive that landed in the position that the Indonesians were holding.

The deaths come shortly after the Israeli military announced it would step up ground and air attacks against the Lebanese armed group Hezbollah.

Hezbollah, an Iranian-backed militia as well as a political party, has fired rockets into Israel in retaliation for the ongoing US-Israeli strikes on Iran.

In a statement on Telegram, the Israel Defense Forces (IDF) said its own review had concluded that the Bani Hayyan explosion was not caused by IDF activity.

Separately, the IDF said on Tuesday that four of its soldiers had been killed in combat in southern Lebanon. Another soldier was severely wounded and a reservist moderately wounded, the IDF said.

Dujarric, of the UN, emphasized that the peacekeepers in Lebanon were soldiers sent there on behalf of the international community... and everyone needs to ensure that they are protected and never targeted.

Antara, an Indonesian government-owned news agency, named the soldier killed on Sunday as Chief Private Farizal Rhomadhon. The two soldiers killed on Monday were named as Captain Zulmi Aditya Iskandar and First Sergeant Muhammad Nur Ichwan.

Created by the UN Security Council in 1978, Unifil has since served as a buffer between Israel and Lebanon, patroling the Blue Line – the de facto border between the two nations. Despite a ceasefire in 2024, daily tensions continue to escalate in the region.