Israel's deputy prime minister Moshe Yaalon warned Damascus on Friday it would act to defend its sovereignty if the bloody fighting in Syria continued to spill over into the occupied Golan Heights.
His remarks, published on his official Twitter account, were made a day after three stray mortar rounds fired from Syria hit the occupied Golan, which Israel seized in the 1967 Middle East war and annexed in 1981 in a move never recognised by the international community.
"We see the Syrian regime as responsible for what is happening along the border," said Yaalon, a senior cabinet minister and former armed forces chief of staff.
"The current situation in Syria could carry on for an extended and bloody period. If we see that it spills over in our direction, we know how to defend the citizens and the sovereignty of the State of Israel," said the minister, who holds the strategic affairs portfolio.
"The other side has received a lot of messages recently and until now, has acted accordingly in Syria. I hope that in this incident too, there will be someone who takes this in hand."
The three mortar rounds which struck the Golan on Thursday were the latest in a string of incidents in which fire has spilled across the ceasefire line onto the Israeli side.
"They are apparently shells fired in error during fighting between different forces inside Syria," an army spokeswoman told AFP.
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On Monday, an Israeli military vehicle patrolling the buffer zone was hit by gunfire, with the army acknowledging it was caused by "stray bullets."
No one was injured but the incident prompted an Israeli complaint to the United Nations Security Council in which it described the gunfire as a "grave violation" of a 1974 agreement on security in the buffer zone.
"This represents a dangerous escalation that could have far-reaching implications for the security and stability of our region," said Israel's UN ambassador Ron Prosor.
"Israel has shown maximum restraint. However, Israel views the continued violations of the Separation of Forces agreement by the Syrian military forces with the utmost concern," he said in a letter to the Security Council.
On Sunday, chief of staff Lieutenant General Benny Gantz warned that Israel could become involved in the Syrian conflict.
"This is a Syrian affair that could turn into our affair," he said on a visit to the sector, without elaborating.
Chief military spokesman Yoav Mordechai, who accompanied Gantz, warned that Israeli troops in the area were "ready at any moment for the fire to change direction and turn on us."
A day earlier, three Syrian tanks entered Bir Ajam village, five kilometres (three miles) southeast of Quneitra, in the demilitarised zone, sparking another Israeli complaint to the UN.
Since Israel and Syria signed the 1974 disengagement agreement, a 1,200-strong unarmed UN force has patrolled the buffer zone.