U.N. spokesman Eduardo Del Buey said authorities from the regional U.N. Disengagement Observer Force reported bad weather conditions in the region.
"UNDOF did not observe any planes flying over the area of separation and therefore was not able to confirm the incident," he said in a statement.
Lebanese resistance party Hezbollah and its allies condemned the alleged attack. Grand Mufti Mohammad Rashid Qabbani, a harsh Israeli critic, was quoted by The Daily Star newspaper as saying Friday that Israel "has taken advantage of the tragic situation of the Syrian people to launch a treacherous aggression against another Arab country."
Syrian forces denied claims that Israeli launched an attack on a military convoy headed to Lebanon. Syria's civil war has threatened to spill over the border.
Ban, in a statement issued by his office, expressed grave concern about the alleged Israeli strike.
"The secretary-general calls on all concerned to prevent tensions or their escalation in the region and to strictly abide by international law, in particular in respect of territorial integrity and sovereignty of all countries in the region," the statement read.