Hezbollah's underground tunnels refer to a network of underground passages used by Hezbollah, primarily in southern Lebanon, along the Lebanon-Israel border. These tunnels are often used for military purposes, such as smuggling weapons, storing supplies, and allowing fighters to move discreetly. The tunnels have been a significant concern for Israel, which views them as a direct security threat. The presence of tunnels near the so-called blue line, as well as incursions into Lebanese territory by other countries, constitute a violation of United Nations Security Council Resolution 1701, such violations contribute to the ongoing tensions between Israel and Hezbollah.