UN peacekeepers are talking to military representatives on both sides of the border after the first fatality in three years.
The Syrian Army and rebels battled for control of Syria's crossing into the Golan Heights. The fighting lasted for seven hours and sent UN peacekeepers scrambling.
Today's incident marks the first time that Syria has admitted breaching the border with Israel since the civil war began.
The Israeli military says its evidence shows that the Syrian regime used sarin gas during a March clash with rebels, reversing earlier reports that no such weapons had been used.