Heavy machine-gun fire from the Gaza Strip on Sunday evening triggered alarms in the southern city of Sderot and other nearby towns, the military said.
No damage was reported in the shooting, which came a day after the Iron Dome air defense system launched interceptor missiles in an incident still under investigation.
It was not clear who had fired the shots or what they had targeted.
A woman in her 30s was treated for anxiety after the sirens sounded in Sderot, the Magen David Adom ambulance service said.
The sirens also sounded in the towns of Gevim, Ibim, Nir Am and Or Haner, as well as at Sapir College.
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The Israel Defense Forces said Iron Dome was not activated during the incident on Sunday, in accordance with its interception protocol.
Machine-gun fire from Gaza, both errant and intentional, has set off alarms in towns close to the border numerous times in recent years.
In another unusual incident on the Gaza border, the IDF said Saturday night that the Iron Dome shot down a drone flying over the Strip, and said that the incident was still unclear several hours later.
Footage showed two Iron Dome interceptor missiles being launched over Sderot, and the army initially said it had taken the drone down.
However, an initial IDF investigation reportedly found that no drone was launched from the Gaza Strip on Saturday night. It still remained unclear what the Iron Dome had actually targeted, if anything.
