Israel said it fired a missile into Syria Sunday, destroying a military post.
The attack came after gunfire from Syria hit an Israeli military vehicle hours earlier.
It is unclear whether the shooting was accidental or was intended to strike at the Israeli army.
No Israeli soldiers were hurt in the incident, BBC News reported.
“The Syrian regime is responsible for every breach of sovereignty. We will not allow the Syrian army or any other groups to violate Israel’s sovereignty in any way,” Israeli Defense Minister Moshe Yaalon said.
The Associated Press said it was the most serious cross-border incident between Israel and Syria since the beginning of the Syrian uprising two years ago.
More from GlobalPost: Moaz al-Khatib resigns as head of Syria opposition
The Tamuz guided missile hit the Syrian army military post where the gunfire originated.
“We were forced to act in a targeted way and to attack and destroy the post from which this (gunfire) took place,” Israeli military chief Lt. Gen. Benny Gantz said Sunday.
“We will continue to operate in the Golan Heights with reason and caution, but where determination and assertive and offensive action is needed, that will also take place.”
Israeli Prime Minister Benjamin Netanyahu also said Saturday that part of his incentive to apologize to Turkey for the Mavi Marmara incident during Obama's visit came from the escalating threat from Syria, according to the Jewish Telegraphic Agency.
"It’s important that Turkey and Israel, which both share a border with Syria, are able to communicate with each other and this is also relevant to other regional challenges," Netanyahu wrote in a Facebook post.
Israel captured part of the Golan Heights, which overlooks Israel and is a very strategic area, from Syria in the 1967 war. It has since annexed the plateau, but that annexation is not recognized by the international community, the New York Times pointed out.
The current line of disengagement was established during the 1973 war, and has become more volatile as the conflict in Syria continues.