The IDF struck back against Gaza's Hamas leadership late Wednesday night, after an estimated 50 Kassam rockets and at least four Grad-style Katyusha missiles pummeled the western Negev and Ashkelon over the course of a few hours in the afternoon, killing a student at Sderot's Sapir Academic College and sending dozens into shock. The IAF fired a series of missiles at the Palestinian Interior Ministry in Gaza, near where Hamas Prime Minister Ismail Haniyeh maintains an office. Haniyeh, who also holds the Interior Ministry portfolio in the Strip, was not in the office at the time, but Palestinians said that 25 people - many of them passersby - were wounded in the attack. The IDF would only say that the air force had struck a number of targets within the Gaza Strip, but would not confirm that Haniyeh's ministry was among the sites targeted. As the air strikes were under way, Defense Minister Ehud Barak was visiting the college in Sderot, where Roni Yihye, 47, a father of four and a student at the school, was killed by shrapnel from a Kassam rocket that struck meters away from where he stood in a parking lot. Barak met with local leaders and police commanders to coordinate a plan of action for emergency responders and civil authorities. The shrapnel lodged in Yihye's chest, and despite the aid of passersby, including a Magen David Adom paramedic who studies at the school, an MDA team was unable to resuscitate him. Another student in the school's parking lot was wounded in the leg by shrapnel, a victim of a second volley of Kassams that hit the Sderot area in less than 90 minutes. Yihye lived in Moshav Bit'ha, near Ofakim, and was a career soldier studying logistics at the college. The largest barrage in recent months began in the early afternoon, when Hamas fired 11 rockets at Sderot, in response, the group said, to the IDF's killing of five Hamas gunmen in the morning. The five, according to security establishment assessments, had recently received training overseas to carry out a major attack against an Israeli target. The Abu Rish Brigades, a branch of Fatah representing a powerful Gaza clan and believed to be allied with Hamas, issued a statement Wednesday afternoon claiming responsibility for the first attacks of the afternoon. But immediately afterward, Hamas issued its own statement claiming responsibility for the rocket that hit Sapir. Both groups said the attacks were a response to IAF strikes in the Gaza Strip. The IAF launched a strike targeting what they said was the Kassam cell responsible for the barrage that killed Yihye. Palestinians claimed that three children were killed and 12 civilians were wounded in that strike. A video released Wednesday showed footage of Kassams fired from residential areas in Gaza, a scenario that makes it difficult to strike back against rocket-launching cells without harming civilians. "The firing of rockets by Hamas at Israeli civilians from within populated Palestinian areas is a war crime that harms both Israelis and Palestinians," the Foreign Ministry said in a statement. "Hamas's terrorism not only endangers the lives of Israeli and Palestinian civilians, it also endangers peace and stability in the region as a whole." Later, in the early evening, four Grad-style missiles, Soviet-made devices similar to the Katyushas used by Hizbullah against communities in the North, and with greater range than Kassam rockets, hit Ashkelon, causing major power outages. One missile struck 150 meters from Barzilai Hospital, where victims of the earlier attacks on Sderot were being treated. Barzilai officials said that other than the windows, the hospital was not reinforced against rocket attacks. In the first barrage of the day, which was unusually large and well-aimed, a rocket slammed through the roof of the Of Kor factory, located less than a kilometer from Sapir in Sderot's industrial zone. It caused massive damage to the workers' dining hall. The dining hall, in which some 150 employees ate lunch less than two hours before the strike, was not reinforced against rocket attacks. One woman, who was cleaning up the remains of the midday meal, was treated for shock. Three other people in Sderot were also treated for shock following the first barrage. The factory's owner, Meir Cohen, said the building had been constructed in the 1960s and had no fortified rooms. Cohen said he had asked the relevant authorities to install protective reinforcement, but that his requests had gone unanswered. In 2006, Of Kor employee Ya'acov Yaakobov was killed when a Kassam - one of almost a dozen to hit the factory in the last seven years - crashed through the ceiling and landed meters away, sending shrapnel into his head. Even after the first two barrages sent nearly 20 rockets at the western Negev, the hail of Kassams continued, with around 30 more rockets fired at Sderot and nearby kibbutzim and moshavim. Starting on Thursday, some bomb shelters in Sderot that had been repaired - and then locked to prevent damage or theft - will be unlocked and made available for use. One such bomb shelter stood only a few meters from where 10-year-old Yossi Haimov was wounded by a Kassam on Monday afternoon.