"Did a war break out or something we don't know about?" one reader wrote.
Notably, Israel has a system of air raid sirens across the country but they are also used for other purposes, such as the traditional Holocaust Day siren.
Sirens at night
The latest incident is not the first time sirens have been heard across the country for no apparent reason in recent months.
Last month, in the middle of the night, sirens were heard going off for a few minutes across the country's Coastal Plain. Among others, Ynet readers in Yahud, Kiriyat Ono, Shoham, and Savion reported the unusual sounds.
Alarmed residents called the police seeking explanations. Police inquiries found that the sirens were activated at an Aircraft Industries facility in Lod.
In October, a siren was heard for 20 minutes in western districts of Rishon Lezion, south of Tel Aviv.
Residents were woken up by the sirens at 12:45 a.m. and many phoned the municipal call center after finding out that the alarm was false. Call center operators told the residents that the matter was being checked, and that the source of the siren was unknown.