GAZA STRIP - Israeli Air Force jets targeted sites in the Gaza Strip overnight after a day of stepped-up Palestinian mortar and rocket fire at southern Israeli communities on Thursday.
Three Palestinians were reportedly killed in the strikes.
The Israeli army said they had targeted four sites including a weapons manufacturing facility in Gaza City; two weapons smuggling tunnels along the border between Gaza and Egypt; and what the army described as a "terrorist tunnel" in the central Gaza Strip.
It is likely that the "terrorist tunnel" was intended for an infiltration attack into Israel. Such a tunnel was used three years ago to mount a cross-border attack from Gaza, in which captive Israeli soldier Gilad Shalit was abducted.
Israel mounted the airstrikes after at least eight mortar shells and a Kassam rocket slammed into Israel on Thursday. The Kassam landed outside the southern Israeli city of Ashkelon. Four of the mortars fell at the Kerem Shalom crossing, where humanitarian supplies pass from Israel into the Gaza Strip.
Some reports said that the Israeli response was the toughest since the end of Operation Cast Lead last January, in which Israel launched a military operation to halt rocket fire at Israeli cities.
More than 300 rockets and mortars have been launched at Israel since then. That's way down from the 3,300 rockets and mortars launched at Israel in 2008, but still an average of nearly one a day.
Many Israeli experts ask which Western country would tolerate those constant attacks from its neighbor.
Earlier on Thursday, the Israeli Air Force dropped leaflets to residents in the Gaza Strip warning them to steer clear of the security fence and stay away from smuggling. The army said that the drop of the leaflets was planned in advance and was not connected with the aerial strikes.
Earlier this week, the head of the army's southern command Maj.-Gen. Yoav Galant warned residents of the south that the (relative) quiet that Israelis experienced recently along the border with the Gaza Strip might not last. He urged them to "prepare themselves for another round of fighting," the Israeli daily Ha'aretz quoted him as saying.