The Israeli military said early on Thursday that several air raid sirens had "sounded in the area of the Golan Heights" and that it was looking into the cause, Reuters reports.
Tensions have been high since US President Donald Trump announced he was quitting the Iranian nuclear deal on Tuesday, prompting Israel to go on high alert.
In a short initial statement on Thursday the Israel Defence Forces said "the details are being looked into" and gave no further details.
On Tuesday the Israeli military said it had identified "irregular activity" by Iranian forces in Syria, and instructed civic authorities on the Israeli-occupied Golan Heights to ready bomb shelters. It also deployed new defenses and mobilized some reservist forces.
Israel's government was a strong supporter of, and advocate for, Trump's decision to quit the Iran nuclear deal and has been readying itself for a possible regional flare-up.
In the run-up to Trump's decision, Israeli Prime Minister Benjamin Netanyahu said in a televised presentation last week that Israel had obtained tens of thousands of pages of what he described as Iran's "secret atomic archives" from what looked from the outside to be a dilapidated Tehran warehouse.
Iran and Lebanon's Hezbollah have been helping Syrian President Bashar al-Assad beat back a seven-year-old rebellion. Israel has carried out repeated air strikes against them, hoping to stop the formation of a Lebanese-Syrian front to its north.
On Tuesday Syrian state media accused Israel of launching missiles at a target near Damascus, shortly after Trump's announcement. Syrian air defenses fired at two Israeli missiles, destroying both, Syrian state news agency SANA.