Israel says Hezbollah, an Iranian-backed militia in southern Lebanon, has set up more than two dozen military outposts along the countries’ border in violation of international agreements, a development it says risks increasing confrontation.

Under a United Nations Security Council resolution following the 2006 Israel-Lebanon war, armed fighters from Hezbollah are not permitted to enter the border area. Troops from the UN Interim Force in Lebanon — or UNIFIL — are stationed there to make sure both sides keep to the rules.

Yet in the past year, Israeli military officials say, those outposts have sprung up along the Blue Line, the boundary set by the UN. Whereas Hezbollah fighters have long entered the area disguised as civilians, some now wear uniforms and openly carry weapons, said the Israeli officials, who were not authorized to speak publicly.

One is said to have ventured 60 kilometers into Israel and set off a bomb, injuring a civilian.

Requests for comment from Hezbollah and the Lebanese Armed Forces went unanswered.

“During the past year Hezbollah has erected at least 27 new military outposts along the Blue Line,” Israel’s ambassador to the UN, Gilad Erdan, wrote in a late June letter to the Security Council. “Since the construction of these outposts there has been a significant increase of friction and incidents, initiated by Hezbollah’s operatives.”

“Hezbollah systematically deprives UNIFIL of its ability to implement its core missions, in order to assure that its military build-up continues unhindered in Southern Lebanon,” he said.

But Israel, too, violates the UN resolution.

According to a UN document from March, Israeli aircraft flew over the Blue Line on 182 occasions between Nov. 3 and Feb. 20 and the country occupies the northern portion of Ghajar, a town that straddles the line. Hezbollah said in recent weeks it had shot down an Israeli drone over south Lebanon.

Escalating Tensions

The developments are just one sign of escalating tensions between Israel and Iran, a nation emboldened by a string of diplomatic breakthroughs including a military alliance with Russia and the restoration of diplomatic ties with Saudi Arabia. Signs even emerged in recent weeks of a potential informal understanding between Tehran and the US, which could lead to Iran voluntarily limiting its nuclear program in return for allowances to ship more crude oil.

Read More: US, Iran Inch Toward Understanding Aimed at Easing Tensions

In contrast, Israeli Prime Minister Benjamin Netanyahu is on the back foot over protests against plans to overhaul the judiciary and last week’s intense fighting in the West Bank, which killed 12 Palestinians and one Israeli soldier.

Read More: As Iran Emerges From Isolation, Israel Is Feeling Cornered

Border Snapshot

A visit to the border accompanied by Israeli military officers illustrates just how close Hezbollah fighters and installations appear to be.

From the roof of an Israeli army border base, a wide green panorama with a red-roofed Lebanese village and Israeli farmland stretches into the distance toward the Hermon mountain range.

Just over the border is a container the officers describe as a Hezbollah military installation. Two people stand on top, snapping photographs of the Israeli side. After a few minutes, a van pulls up on the Lebanon side, and half a dozen men get out. The group walks over to the roof of a nearby building. The officer in charge of the installation walks closer. The two sides stare at each other.

UNIFIL doesn’t deny there is cause for disquiet.

“Any presence or activity on the north side of the Blue Line not belonging to UNIFIL or the Lebanese Armed Forces is a concern,” Kandace Ardiel, a spokesperson, said. “Peacekeepers must have full freedom of movement along the Blue Line and throughout our area of operations.”

A UN report from March says despite repeated requests, “UNIFIL has yet to gain full access to several locations of interest.”

Israel is increasingly concerned about Iranian activities, and not just in Lebanon. Last week, the Israeli military raided a refugee camp in Jenin, its biggest such incursion into the West Bank in two decades. Part of the goal was destroying weapons-production sites it says were controlled by Iran-funded terrorists.

On Thursday, a rocket was launched from Lebanon at Israel, and the Israeli military struck back.

Fully-Fledged Military

Hezbollah, funded mostly by Iran and thought to have more than 100,000 rockets and missiles at its disposal, would be certain to play a role in any bigger conflict. Israeli officials speculate the group has been encouraged by the return to Lebanon of personnel who fought in Syria, who have transformed the group from a guerrilla outfit to a fully-fledged military organization with professional soldiers.

Israeli officials say that as Lebanon declines further into one of the worst economic and financial crises in history, Hezbollah is getting more powerful. And Lebanon’s official army, the Lebanese Armed Forces, isn’t strong enough to police it.

--With assistance from Dana Khraiche, Thomas Hall and Paul Richardson.