The newly signed US-Iran agreement is already facing its toughest test, as Israeli strikes on southern Lebanon continue to kill civilians in and around Nabatieh, threatening to unravel the fragile truce just days after it was announced.

Despite the deal being formally signed this week to end hostilities across the region, Israeli drone and air strikes have repeatedly hit the Nabatieh district, with casualties reported in towns including Kfar Tebnit, Mayfadoun, Shoukine, and Zebdine. Lebanon's National News Agency has documented a string of attacks since the agreement was announced, even as violence overall has declined compared to earlier in the conflict.

Israel says it intends to maintain a security presence in parts of southern Lebanon and has published a map of a so-called "security zone" extending roughly 10 kilometers into Lebanese territory. Israeli officials argue this is necessary to "remove threats" and protect troops, who have also come under attack from Hezbollah drones and rockets near Nabatieh.

Iran, for its part, has warned that continued Israeli strikes and occupation of Lebanese territory would constitute a violation of the US-brokered agreement. Iranian Foreign Minister Abbas Araghchi has stated that Tehran's understanding with Washington explicitly requires Israeli withdrawal from Lebanon — a condition Israel disputes.

Hezbollah claims to have repelled a multi-day Israeli push toward strategic high ground near Nabatieh, using drones, rockets, and artillery against Israeli armor. Meanwhile, the G7 has called for an "immediate robust ceasefire" and supported Lebanese efforts to disarm Hezbollah and restore sovereignty, according to a report from Al Jazeera.

With both sides accusing the other of bad faith, and Israeli-Lebanese talks ongoing separately in Washington, the central question now is whether the broader US-Iran framework can survive sustained fighting on the Lebanon front — or whether Nabatieh becomes the flashpoint that breaks it.