The UN peacekeeping force in Lebanon, which says it has come under repeated fire in the Israeli-Hezbollah war in recent days, has patrolled the troubled border for decades.
Here is an overview:
Ceasefire monitors
The United Nations Interim Force in Lebanon (UNIFIL) was set up in 1978 to monitor the withdrawal of Israeli forces after they invaded Lebanon to stem Palestinian attacks targeting northern Israel.
Israel again invaded in 1982, only withdrawing from south Lebanon in 2000.
UNIFIL's role was bolstered by UN Security Council Resolution 1701 after Lebanese militant group Hezbollah and Israel fought a war in 2006.
Its peacekeepers were tasked with monitoring the ceasefire between the two sides.
The mission has its headquarters in the southern Lebanese town of Naqura, which in recent years has hosted indirect talks on a final border between both sides.
UNIFIL troops carry out patrols along the Blue Line between Lebanon and Israel in coordination with the Lebanese army.
They are also tasked with helping to support the needs of civilian populations.
From Indonesia to Ireland
The Security Council in late August extended UNIFIL's mandate for another year.
The peacekeeping mission includes about 10,000 total personnel, more than 9,500 of which are troops from various countries.
The soldiers hail mostly from Indonesia, India, Ghana, Nepal, Italy, Malaysia in terms of numbers, but also Spain, France, China and Ireland.
The mission is headed by a Spanish general, Aroldo Lazaro.
Over the years since 1978, it has lost 334 members.
Hezbollah tunnels
Resolution 1701 called for the Lebanese army and UN peacekeepers to be the only armed forces deployed in the country's south.
Hezbollah has not had a visible military presence in the border area since 2006, but it holds sway over large swathes of the south, where it has built tunnels and hideouts, and from where it has launched attacks.
'Liaison channel'
In the past, UNIFIL patrols have occasionally faced harassment, and in December 2022 an Irish soldier with the force was killed and three colleagues wounded when their convoy came under fire in south Lebanon.
After Palestinian militant group Hamas attacked Israel on October 7 last year, sparking the latest Gaza war, Hezbollah started trading near daily cross-border fire with Israeli forces in support of its Islamist ally.
The global chief of UN peacekeepers Jean-Pierre Lacroix said in August that UNIFIL's job was "more important than ever", as a "liaison channel" between both sides.
He said they were key in informing all sides when, for example, rescuers need to help wounded or retrieve people who had been killed.
Wounded peacekeepers
The mission has called for a ceasefire since an escalation between Israel and Hezbollah on September 23.
Israel has since last week announced "targeted" incursions into Lebanon against the Iran-backed group, which has repeatedly announced it is repelling Israeli troops along the border.
UNIFIL has said headquarters and nearby positions "have been repeatedly hit" in recent days, sparking international condemnation.
It also said an Israeli tank fired at a UNIFIL observation tower on Thursday, injuring two Indonesian Blue Helmets.
On Friday the mission said a pair of explosions wounded two Sri Lankan members of its team after two explosions occurred close to an observation tower.