Police spokesman Micky Rosenfeld told reporters the shells fired into the city of Shlomi were 107mm Katyusha rockets that have a range of 15 miles, CNN reported.
Bomb squad officials who examined the impact sites said "this attack does not show any tell-tale signs of being Hezbollah-initiated," Ynetnews.com reported.
The Israeli military said its radar didn't identify the launching of the rockets, although Ynet said a thunderstorm was going on at the time.
A similar incident happened last June and Hezbollah denied launching those. This time, a Hezbollah spokesman told CNN he couldn't confirm if the organization was responsible.
During the Israeli-Lebanese second war in the summer of 2006, hundreds of the Katyushas rained into Israel. In the Gaza Strip, Palestinian militants use the shorter-range Qassam rocket in attacks on Israel.