At least 11 Palestinian civilians, including four children, were killed on Sunday in what Hamas said was an Israeli airstrike on a Gaza apartment building, Palestinian reports said. Five women, including one 80-year-old, and four small children were among the dead, said Gaza health official Ashraf al-Kidra. It was further reported that seven of the dead were members of the same family and that 25 people were hurt in the attack. Related stories: Netanyahu: First stop firing, then we'll talk Obama: 'Preferable' to avoid ground op Grad hits near car in Ofakim 5 wounded A spokesman for the Hamas-run Interior Ministry said an Israeli missile wrecked the three-storey residential building. "The massacre of the Dalu family will not pass without punishment," Hamas's armed wing said in a statement. The IDF initially said that the head of Hamas' rocket unit Yahia Rabia was killed in the strike but it later corrected itself saying he is a high-ranking operative within the unit and was possibly not even hurt in the strike. A Gaza source said that the target was apparently Jamal Mohammed Yassin Dalu, 50, an engineer. Dalu is likely linked to the rocket unit. However, the source said that Dalu and Rabia are not connected. Four kids killed in strike (Photo: AFP) It is possible there are more bodies under the rubble, including that of Rabia. There were no reports about him in Gaza. It is possible that the IDF bombed the wrong building but it is equally as likely that the Palestinians are withholding information about the residents of the building. Hamas' military wing vowed to avenge the Palestinians' deaths and stated that "the massacre will not go unpunished." The IDF did not comment on the attack. Meanwhile, Palestinian sources are reporting that Air Force jets fired warning missiles near the house of Marwan Issa, a senior operative in Hamas' military wing. Issa has been mentioned as one of the possible successors of Ahmed Jabari. The strike on Issa's house was carried out following a direct order by IDF chief of Staff Benny Gantz to hit Hamas officials. Palestinian sources also reported that 19 people were killed in IDF strikes in Gaza and 66 in total since the beginning of Operation Pillar of Defense. Medics in Gaza said that the two men who were killed in the strike were civilians and not members of Hamas or the Islamic Jihad. Reuters and AP contributed to this report Follow Ynetnews on Facebook and Twitter Receive Ynetnews updates directly to your desktop