Ayala Shapira, the 11-year-girl who was critically injured on Thursday when a firebomb was thrown at a private vehicle in the West Bank, remains in serious condition on Friday, as doctors continue fighting to save her life.Though her situation slightly improved overnight, she is still in serious condition, the Sheba Medical Center at Tel Hashomer said in a statement, anesthetized in the hospital's emergency department. "We will lay our hands on the perpetrators of this terror attack," said Defense Minister Moshe Ya'alon at Ma'ale Shomron, where he was updated by security officials on the situation, "and we will reach their dispatchers." The response to the attack was swift, Ya'alon said, praising the IDF and Israel's Security Agency, the Shin Bet, for "knowing how to effectively respond to terrorism" and deploying quickly to the scene as events were unfolding. Fighting these types of attacks is complicated and requires determination and the use of force – "something Israel is doing now and will continue to do." The defense minister visited Ayala at the Sheba Medical Center where he encouraged her family to "be strong," assuring the worried parents that she is "in good hands." These acts of terror, he said at the hospital, are meant to instill fear in the residents of Judea and Samaria. "But from my many conversations with them, it is clear they will not be deterred."The firebomb attack near Ma'ale Shomron left Ayala severely burned and her father, Avner Shapira, more lightly injured after their car was set ablaze. The girl suffered third-degree burns over 30-40 percent of her body. The incident occurred east of Kalkilya in the West Bank, where the IDF launched a widescale search for the attackers. The army arrested 12 Palestinians in an overnight raid in the area, taking them into custody for possible ties with the attack.Prime Minister Benjamin Netanyahu spoke to Yossi Dagan, the acting head of the Samaria Regional Council, following Thursday evening's incident. "Tell the family we stand by their side and wish them a fast recovery," Netanyahu said.Dagan briefed the premier on the happenings of Thursday's incident, telling him of the terror-filled reality that Samaria residents deal with on a daily basis, with the constant threat of stone throwing and fire bombs.He asked Netanyahu to react to the attack by strengthening the settlement movement. "The most appropriate response to terror of this kind against innocent civilians is strengthening Jewish settlement," Dagan said.Terror in Samaria must be addressed by building, developing, and expanding Jewish settlement in the region, he added.