This was after the Israeli military notified them that it would be releasing what it described as a non‑toxic chemical substance near the frontier, the UN said on Monday.

According to UN Spokesperson Stéphane Dujarric, the incident occurred north of the Blue Line on Sunday morning and resulted in more than a dozen peacekeeping activities being paused for over nine hours.

“The Israel Defence Forces (IDF) said that peacekeepers should stay clear of the area,” Dujarric told reporters in New York. He confirmed that UN personnel had assisted the Lebanese Armed Forces in collecting samples of the substance, which are now undergoing toxicology testing. As of Monday afternoon, the results had not yet been received.

The Blue Line stretches roughly 120 kilometres along Lebanon’s southern border and acts as a “line of withdrawal”, verifying Israel’s pull‑out from southern Lebanon.

The UN reiterated concerns about military flight activity across the Blue Line, noting that such movements violate Security Council resolution 1701, which ended hostilities between Israel and Hezbollah in 2006 and outlines the mandate of the UN Interim Force in Lebanon (UNIFIL).

The most recent cessation‑of‑hostilities agreement between the parties was signed in November 2024 following renewed clashes across the Blue Line after the outbreak of the Gaza conflict. “Any activity that may put peacekeepers and civilians at risk is of serious concern,” Dujarric said. “We reiterate our call on all parties to fully comply with their obligations under resolution 1701.”

UNIFIL said the incident also raised concerns about possible effects on civilians, agricultural land, and the long‑term return of residents to their homes near the Blue Line.

“This is not the first time that the IDF has dropped unknown chemical substances from airplanes over Lebanon,” the mission said. It reiterated its call on the Israeli military “to stop all such activities and work with peacekeepers to support the stability we are all working to achieve.”

–UN/ChannelAfrica–