Palestinian boy killed as Israel, militants trade fire June 23, 2012 -- Updated 1107 GMT (1907 HKT) Palestinian medics tend to a man wounded during Israeli air strikes in Gaza on June 23, 2012. Palestinians say Israeli artillery fire killed the boy The IDF says the boy died from terrorist "ordnance" Palestinians report injuries from a flurry of strikes overnight Israel says a man near Sderot was seriously injured Jerusalem (CNN) -- A 4-year-old Palestinian boy was killed in Gaza on Saturday as Israel and Palestinian militants continue to trade fire in an upsurge of unrest at the tense Israeli-Gaza border. Palestinian medical officials said Israeli artillery fire from a tank at the Israeli-Gaza border killed the boy and badly injured two other civilians. Israel Defense Forces spokeswoman Lt. Col. Avital Leibovich sent out a Twitter message saying the explosion causing the child's death was from an "ordnance belonging to one of the terrorist groups." Reports indicating that a Palestinian child was killed by IDF activity are false, Leibovich said. Israel has been pounding targets in Gaza because of sustained rocket fire into the country from militants in the Palestinian territory. Militants have been firing rockets to retaliate for the airstrikes. The latest incident occurred east of Khan Younis in southern Gaza. Palestinian medical officials reported other incidents. An airstrike by an Israeli drone killed one man when it hit a militant group east of Beit Lahiya, north of Gaza, according to medical sources in Gaza. An Israeli drone fired a missile at a car in the Zeitoun neighborhood south of Gaza City, injuring three people. At least 12 others were injured in three Israeli airstrikes overnight, medical officials said. Also, a tank shell struck a parking lot in downtown Gaza City but did not explode. The IDF said more than 15 rockets had been fired into Israel on Saturday morning alone. The IDF also said some rockets have been intercepted by the country's Iron Dome missile system. Senior IDF officers held an urgent meeting to determine the military's "course of action." The IDF said its airstrikes have targeted sites in response to the week's "continuous rocket fire toward southern Israel. During the past week over 135 rockets hit Israel. Near the city of Sderot, in Israel, a 50-year-old man was seriously injured when he was hit in the neck with shrapnel from a rocket that exploded at a factory. Alon Shuster, head of the Shaar Hanegev Regional Council in Israel, said citizens would not be forced out by the attacks. The residents of this region who have tolerated this situation over the past 12 years will continue to stay here. It is the government's responsibility to ensure our safety, whether by a political or military action and not allow these fictitious truces any longer," he said. CNN's Guy Azriel and Kareem Khadder in Jerusalem and Talal Abu Rahma in Gaza contributed to this report.