The United Nations Interim Force in Lebanon had said that the peacekeeper was killed on Sunday evening when a projectile of unknown origin "exploded in a UNIFIL position near Adchit al Qusayr".

The source told AFP on condition of anonymity that investigations had shown the fire came from an Israeli tank, adding that "debris from a tank round has been recovered" at the site.

On Monday, UNIFIL said another "explosion of unknown origin" destroyed a peacekeeping vehicle, killing two more Indonesian troops, and that an investigation had also been launched into that incident.

The UN security source said the origin of that explosion may have been a mine.

Israel's military denied responsibility for Monday's incident.

"A comprehensive operational examination indicates that no explosive device was placed in the area by IDF troops, and that no IDF troops were present in the area at all," it said in a press release.

In an earlier statement, it noted that "these incidents occurred in an active combat area", and that "it should not be assumed that incidents in which UNIFIL soldiers were harmed were caused by the IDF".

UNIFIL numbers some 8,200 peacekeepers and patrols Lebanon's de facto southern border area, where Israel and Hezbollah have been fighting since war erupted this month as Israeli troops pursue a ground offensive.

The UN Security Council was holding an urgent meeting on Tuesday at the request of France after the peacekeepers' deaths.

France's Foreign Minister Jean-Noel Barrot on Monday accused Israel of unspecified "security breaches and intimidation" experienced by the French UNIFIL contingent in Naqura, where the mission's headquarters are located.

Barrot said that anger had "been conveyed with the utmost firmness to the Israeli ambassador in Paris".