Israel intercepted a drone launched from Syria with a Patriot missile on Wednesday, setting off sirens in the occupied Golan Heights, the army said.
"UAV from Syria intercepted by Patriot missile, causing sirens in Golan and Emek HaYarden Regional Councils," an army statement said.
The Emek HaYarden region is located southwest of the Golan, near Syria.
A later military statement said the drone had "infiltrated the Israeli border", without providing further details.
"The aerial defence systems identified the threat and tracked it," the army said.
Israeli police called on all boats to move out of the Sea of Galilee, which is located in the area, "due to security operations".
Israel has been on alert in recent weeks over fighting in the south of neighbouring Syria, warning that ceasefire lines between Syria and Israel must be respected.
Spillover fire from Syria's civil war has occasionally landed in the Israeli-controlled Golan.
Israel is especially concerned about Iran's military presence in Syria.
Israeli Prime Minister Benjamin Netanyahu has repeatedly warned his country will not allow Iran, its main enemy, to entrench itself militarily next door.
In February, Israel intercepted what it said was an armed drone sent into its territory by Iran.
A series of strikes in Syria that have killed Iranians have been attributed to Israel in recent months.
Iran is backing Syrian President Bashar al-Assad in the war, as is Russia.
Wednesday's incident came as Netanyahu travelled to Russia to meet President Vladimir Putin.
Israel seized a large swathe of the Golan Heights from Syria in the 1967 Six-Day War and later annexed it, in a move never recognised by the international community.