IDF troops conducted house-to-house searches in the southern Gaza Strip and killed three Palestinians with tanks and air strikes early Friday, Palestinian officials said, in the latest stage of Israel's monthlong offensive against terrorist infrastructure. Three Palestinians were killed by Israeli fire in two separate incidents before daybreak Friday, hospital officials said. Hamas said two of the casualties were Hamas members. The army said in a statement its forces targeted 25 gunmen carrying anti-tank missiles who were planting explosives in the army's area of operations. It didn't mention casualties. Armored forces regrouped overnight on the outskirts of the town of Rafah as the searches were under way, the army said. Israeli aircraft also hit two houses in Gaza City with missiles. Residents said the military warned occupants to leave before the attacks, and no one was hurt. Also Friday, Palestinian and Israeli officials and European monitors agreed to reopen the Gaza-Egypt border crossing on Saturday and Sunday for one-way traffic into Egypt, said Palestinian negotiator Saeb Erekat. The crossing was intended for students to return to schools, for businessmen and for humanitarian cases, he said. It would be the second time since the latest fighting erupted in Gaza June 25 that the terminal would be opened, but the previous time was for Palestinians returning home from Egypt. Earlier agreements to reopen the crossing from Gaza to Egypt broke down at the last minute. Israel, which has been criticized for creating a humanitarian crisis in Gaza, said it opened another border checkpoint to allow 160 truckloads of food and medical supplies into Gaza, as well as gasoline and diesel. The United Nations said Thursday it was concerned that "with international attention focusing on Lebanon, the tragedy in Gaza is being forgotten." It called on both Israel and the Palestinian militants to recognize their obligations to protect civilians during hostilities, but singled out Israel for criticism. Israel launched its Gaza offensive after a June 25 cross-border raid by Hamas-linked operatives who tunneled into Israel and attacked an army post, killing two soldiers and capturing a third. Israel has demanded the release of the soldier and an end to the firing of homemade rockets at Israel by terrorists in Gaza. Ground forces have moved in and out of several parts of the territory regularly since then, confronting armed militants and leaving behind considerable destruction. Flyers dropped in Gaza by the IDF on Thursday portrayed the exiled political leader of Hamas, Khaled Mashaal, as a gambler. A cartoon drawing showed Mashaal holding three cards reading "security," "prosperity" and "future" with a message saying he was "gambling with the future of Palestine and bringing disappointment, despair and destruction" to Palestinians.