Lebanon's state media said an Israeli air strike targeted the Baalbek region in the east of the country before dawn on Wednesday, branding it a "violation" of the fragile ceasefire between Israel and Hezbollah.
The truce went into effect on November 27 after more than a year of hostilities that began with the outbreak of the war in the Gaza Strip.
Both sides have since accused the other of breaching the ceasefire.
Wednesday's strike near the town of Tarya did not result in casualties, the state-run National News Agency said, calling the attack the "first violation of the ceasefire agreement" in the Baalbek area.
A Lebanese security source, speaking on condition of anonymity, said the strike targeted "warehouses believed to belong to Hezbollah".
Hezbollah has for decades held sway in south Beirut, and the south and east of the country.
The war with Israel saw Hezbollah massively weakened but not crushed.
A committee made up of the United States, France, Lebanon, Israel and United Nations peacekeepers is tasked with monitoring the ceasefire and ensuring violations are identified and dealt with.
Lebanon has asked the parties -- particularly the United States and France -- to press Israel to speed up its withdrawal from the country's south under the terms of the deal.
As part of the truce, the Lebanese army and peacekeepers will deploy in southern Lebanon as the Israeli army pulls out over a period of 60 days, which are due to expire in January 2025.
The Israeli army said on Monday that it was continuing its "defensive activities" in the south "in accordance with the agreement".
It has yet to issue a statement on the reported strike in eastern Lebanon.