A man and his two children crossed the border from Lebanon into Israel on Wednesday and were immediately detained by Israeli troops, witnesses and the Lebanese state news agency reported.
The incident took place at the Fatima Gate in southern Lebanon, facing the Israeli town of Metula, the agency said.
Witnesses interviewed by an AFP correspondent identified the man as a Palestinian in his 30s.
They said he threw two small infants over the fence separating both countries before scaling the barrier himself.
The three were immediately picked up by Israeli troops, witnesses said.
One of the children got caught up in the barbed wire and was injured, one witness said.
Members of the UN peacekeeping force stationed in southern Lebanon and army troops immediately rushed to the site.
A UNIFIL spokesperson had no immediate comment.