Under a November ceasefire that sought to end more than a year of hostilities including two months of open war between Israel and Hezbollah, Lebanon's army has been deploying in the country's south and dismantling the Iran-backed group's infrastructure there with the support of UN peacekeepers.

"While army personnel were inspecting an Israeli enemy drone after it fell in the Naqura area, it exploded, leading to the death of an officer and a soldier and wounding two other personnel," the army said in a statement.

President Joseph Aoun said in a statement that "the army is once again paying in blood the price of maintaining stability in the south."

He said it was the fourth deadly incident for the army since it began deploying in south Lebanon after the ceasefire.

Earlier this month, six Lebanese soldiers were killed in a blast at a weapons depot near the border that a military source said belonged to Hezbollah.

Aoun noted Thursday's incident coincided with the United Nations Security Council's extension of the UN peacekeeping force's mandate ahead of its withdrawal at the end of 2027.

It also coincided with "the international community's call for Israel to halt its attacks, withdraw... and enable the Lebanese army to complete the extension of its authority up to the international border", the presidency statement said.

Under the US-brokered ceasefire, Hezbollah and Israel were both required to withdraw from south Lebanon, but Israel has kept troops in several areas it deems strategic.

Reacting to Thursday's incident, Prime Minister Nawaf Salam expressed his condolences and the government's "full solidarity with the military institution".

He said the army was Lebanon's "safety valve, the stronghold of sovereignty and the support of national unity".