The image appears to show an Israeli soldier using a sledgehammer to strike the head on a statue of a crucified Jesus that had fallen off a cross.
The sculpture is located in the Christian village of Debl in south Lebanon, near the border with Israel, the local municipality told AFP, but officials could not say whether it had been damaged.
Israel’s army said in a post on its official X account on Monday that it viewed the incident with “great severity”, adding that the “soldier’s conduct is wholly inconsistent with the values expected of its troops”.
“Following the completion of an initial examination regarding a photograph published earlier today of an IDF soldier harming a Christian symbol, it was determined that the photograph depicts an IDF soldier operating in southern Lebanon,” the army said.
The incident is being investigated by the Northern Command and is currently being “addressed through the chain of command”, it added.
The army said “appropriate measures will be taken against those involved” but did not go into further detail.
It said it is working with the community to “restore the statue to its place”.
Israeli Foreign Minister Gideon Saar condemned what he called a “shameful and disgraceful” act.
“I am confident that necessary severe measures will be taken against whoever committed this ugly act,” he wrote on X.
“We apologise for this incident and to every Christian whose feelings were hurt.”
Lebanon was drawn into the Middle East war in early March when the Tehran-backed armed group Hezbollah launched rockets towards Israel in support of Iran.
Israel responded with massive strikes across Lebanon and an invasion of the south.
Israeli troops have remained in the south despite a ceasefire between the two countries that began on Friday.