According to the Lebanese National News Agency, the device was sent over the border in the early hours of Monday.
The report comes after the Lebanese Army said on 1 September that Israel had fired over 40 missiles near the settlements of Maroun El Ras, Aitaroun and Yaroun.
The shelling followed Hezbollah’s anti-tank missile destroying Israeli armoured vehicles in the border area in retaliation against Israel’s drone attacks. Lebanon has also accused Israel of being behind Sunday drone strikes on Hezbollah's headquarters near Beirut and Palestinian military positions in eastern Lebanon.
For months, Lebanon has objected to Israeli anti-Hezbollah operations in its airspace, insisting that they violate the country's sovereignty and UN Security Council Resolution 1701 intended to resolve the 2006 Israel-Lebanon conflict. Israel, in turn, considers Lebanon-based Hezbollah its key rival in the region and conducts regular air raids against it.