Israeli Prime Minister Benjamin Netanyahu renewed accusations this week that Iran was planning to build missile factories in neighbouring Lebanon, a claim that has raised tensions on the two countries’ disputed border to the highest they have been in years.
That claim, which Mr Netanyahu addressed with President Donald Trump during a US visit, comes along with Israel's construction of a wall and disagreements with Lebanon over possible petroleum deposits.
Stepping in to mediate, as it has for decades, is the United Nations Interim Force for Lebanon (Unifil) – which will mark its 40th anniversary later this month.
“It’s not exactly a celebration,” said Unifil spokesman Andrea Telenti.
He said that low-key events are planned to mark the occasion, including a photo exhibition and asking residents of southern Lebanon – many of whom in the past have endured heavy Israeli bombardment – to recall their memories of Unifil.
Created by UN Security Council resolution 425 in 1978 to monitor Israel's withdrawal from southern Lebanon, the force's mandate and size were expanded in 2006 after the end of the most recent conflict between Hezbollah and the Israeli military.
Unifil’s role has remained largely uncontroversial since then, with its primary purpose being to report violations on and around the Blue Line, as the line of withdrawal is known. Its approximately 10,500 soldiers conduct more than 13,000 operations, mostly patrols, each month.
But in August of last year, as the UN prepared to renew Unifil’s mandate, US ambassador to the UN Nikki Haley criticised the force for failing to stop Iran and Hezbollah from “smuggling” weapons into southern Lebanon.
Her remarks that Unifil was not aggressive enough appeared to be part of a wider effort by the Trump administration to counter the growing regional influence of Iran and its Lebanese proxy, Hezbollah.
"It's time the Security Council puts teeth in the Unifil operation," Ms Haley said, calling the force's head of Mission and Force Commander Maj Gen Michael Beary "blind to what Hezbollah is doing".
Since 2006, Unifil has operated UN resolution 1701 – which ended the Israel-Hezbollah war – and Ms Haley's complaints led to the adoption of UN Security Council resolution 2373, which called for the "full implementation" of resolution 1701 and for "all concerned parties to strengthen their efforts … without delay".
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An official with the US mission to the UN said that the US government was satisfied so far with the implementation of resolution 2373.
"We believe this resolution will help ensure Unifil has an explicit mandate to do its job," the official said.
"It will significantly improve and strengthen Unifil's ability to act more visibly in its area of operations, step up patrols and inspections to disrupt Hezbollah's illicit activities, and ensure Unifil is acting within the fullest extent of its mandate."
But six months later, it is unclear what is different on the ground. Unifil has continued its patrols with no real changes and continues to report violations on the ground near or along the Blue Line, the most common being of hunters carrying rifles or shepherds inadvertently crossing the undemarcated border.
"The main basis of the mandate has not changed," Mr Telenti said. "With all this patrolling, with all these activities, we have not seen or been provided with evidence of weapons coming into southern Lebanon. We are not everywhere in the country, but we have not seen the entry of any new weapons."
Lt Luis Fernandez Perez Amo, spokesman for Unifil's Spanish contingent, said during a routine patrol earlier this month: "The ultimate goal is to have a presence."
As the patrol stopped on a ridge overlooking the border near the town of Ghajar, Lt Perez Amo pointed out a memorial marking the spot a French peacekeeper had been killed in 2005.
Unifil has lost 325 soldiers since its creation, the most recent casualty in 2015 near Ghajar being a Spanish peacekeeper, who was killed as Hizbollah and the Israeli forces traded rocket and artillery fire.
Ghajar itself is also a “permanent violation” of the Blue Line. The town straddles the border but has been claimed by Israel in its entirety.
The case of Ghajar and Israel’s plan for a wall are two of the reasons Unifil is seeking to formally mark the border.
"On both sides, we have no border. The Blue Line is just a line of withdrawal – and marking the Blue Line has been an effective tool to make sure there are no violations from either side," Mr Telenti said.
The process involves placing barrels at intervals along the Blue Line.
"Each barrel has to be measured by both sides," Mr Telenti said, noting that a disagreement of even 50 centimetres can be problematic.
“So it has to be very precise. So far more than 150 barrels have been positioned along the Blue Line.”
Mr Telenti has been with Unifil since 2006, when the last conflict between Israel and Hezbollah took place, and notes that significant changes have occurred in south Lebanon since then.
"When I arrived here in 2006, there was nothing. Most of the villages were destroyed. Now you see roads and infrastructure and people investing in the south. There have been 11 years of peace," Mr Telenti said.
“Peace is addictive. Once you get used to it, it can be hard to go back. It’s very important that we nourish this culture of peace.”