"I deeply regret the terrible accidents that caused the deaths of innocent Palestinians," Prime Minister Ehud Olmert said on Thursday in response to the recent surge in civilian casualties on the Palestinian side. According to Olmert, "This, by no means, is our policy, but rather unfortunate mistakes." Following the second botched IAF strike in the Gaza Strip in as many days, in which two people were killed and 13 wounded when a missile hit a house in Khan Yunis, IDF Chief of General Staff Lt.-Gen. Dan Halutz on Wednesday ordered an investigation into recent air strikes that wounded civilians. The IDF confirmed that it fired two missiles at a car carrying members of a terror cell affiliated with the Hamas-backed Popular Resistance Committees on their way to what IDF officers described as a "large-scale" terror attack. One of the missiles missed the car and hit a nearby building, killing pregnant Fatma Abdel Khader, 35, and her brother, Zakaria Ahmed, 45, visiting from Saudi Arabia. [For a Jerusalem Online video of events click here] Defense Minister Amir Peretz met with Halutz, who updated him on the missile strike and informed him of his order to the IAF to thoroughly investigate the botched attack. Peretz, sources in his office said, instructed Halutz to order the IAF to cancel future missions if there is was a chance that innocent civilians would be harmed. OC Air Force Maj.-Gen. Eliezer Shkedy said Wednesday night that the IDF planned to continue striking terrorists from the air despite the recent failures, although under more stringent guidelines. "This is the only way nowadays to strike terror in Gaza," Shkedy said. "The other alternative is a ground incursion and we need to do everything we can to prevent this, although the possibility exists and the other side knows it." Terrorists, Shkedy revealed, have understood that the primary threat against them was from the air and had in recent weeks changed their tactics in the way they launch rocket attacks. He said they fired rockets mostly from within densely populated areas, sometimes inside buildings and backyards. "We will continue fighting terror," he added. "And we will do all we can to protect the citizens of Israel and to target terrorists without harming innocent civilians." Meanwhile, sources in Palestinian Authority Chairman Mahmoud Abbas's office said he will express his deep concern over Israel's ongoing policy of targeted killings and will urge Prime Minister Ehud Olmert not to launch a massive IDF operation in the Gaza Strip. "President Abbas will warn that an Israeli military operation will only complicate matters and will plunge the Palestinian territories into more violence and bloodshed," said one source. "Obviously, an Israeli military operation now will play into the hands of Hamas and undermine the moderates among the Palestinians and this is what Olmert needs to understand." Moments after the botched attack, Peretz took the podium at the Caesarea Conference in Jerusalem and was passed a note informing him of the results of the strike. Peretz lowered his head and told the crowd: "I am in the midst of a complicated period... as defense minister. I would like to try out my beliefs as a man of peace since I believe that dialogue is the solution." A witness said the car carrying the terrorists passed the house as the missile struck. They jumped from the car and ran into a nearby field. The missile, a high-ranking IAF officer said, missed its target by almost 30 meters, a severe failure. A statement from Abbas' office harshly condemned the Israeli attacks. "The increased frequency of women and children falling victims to Israeli missiles, in an age of very precise electronic warfare, indicates a deliberate intention on the Israeli part to target every Palestinian and to cause maximum human, physical, and psychological damage," it said. Earlier in the day, IDF troops killed two Palestinians during arrest raids in the Nablus area. One was identified as Daoud Katouni, a senior Tanzim terrorist, behind the suicide bombing outside Kedumim in March in which four Israelis were killed. Katouni was also behind a thwarted suicide bombing last month, when IDF troops caught two Palestinians carrying an explosive belt on the way to a target.