The Israeli Air Force early Friday morning retaliated against rocket fire into southern Israel hours earlier by bombing the Gaza Strip.

According to the IDF, Israeli planes hit “a terror activity site and a weapon manufacturing facility in the northern Gaza strip and a weapon storage facility in the southern Gaza Strip.”

Unconfirmed reports from Gaza indicated as many as five injured in the strikes.

Palestinian security sources said two strikes targeted training sites of the Izz ad-Din al-Qassam Brigades, Hamas’s armed wing, in Beit Lahiya in northern Gaza. In two additional air strikes, at sites west of the southern Gaza city of Rafah, two Palestinians were injured, the sources said.

“Israelis cannot be held at the mercy of these hideous terrorists operating from Hamas’s Gaza Strip,” IDF spokesperson Lt. Col. Peter Lerner said in a statement. “The bases of Gaza terrorism and its industry of death will not be immune while our citizens are being attacked. It is our responsibility, right and obligation to defend Israel from Gaza-based aggression.”

A video uploaded to YouTube claimed to show the Israeli airstrikes hitting the Gaza Strip early Friday morning.

Earlier in the evening, sirens wailed in the southern city of Netivot as a Grad rocket fired from the Gaza Strip exploded in an open area outside town.

There were no injuries or damage reported in the incident. Security forces retrieved the remains of a projectile that landed outside the city, which is home to over 26,000.

Thursday night’s incident marked the first time since November 2012’s Operation Pillar of Defense that air-raid sirens went off in the southern town as a result of rocket fire from the Hamas-controlled Gaza Strip.

Last Wednesday, the Israeli Air Force launched an airstrike in the northern Gaza Strip town of Beit Hanoun, killing at least one man, said by Israel to be a terrorist. According to the IDF, Israel targeted and hit Ahmad Zaanin, 21, a member of a Gaza-based Popular Front for the Liberation of Palestine’s military wing, responsible for recent rocket fire against Israel. It said he fired the rockets that targeted Israel after the funeral for prime minister Ariel Sharon earlier in January.

AFP contributed to this report.