A new military investigation into the 2008 battle at Wanat, Afghanistan, one of the deadliest engagements of the war, will examine whether decisions by senior commanders contributed to the deaths of nine American soldiers in the firefight, officials said Thursday. Previous inquiries focused on decisions and actions by the small unit assigned to a remote outpost in Wanat in northeastern Afghanistan, which was almost overrun in a surprise attack by insurgents. The vicious, four-hour battle also left more than 30 U.S. and Afghan troops wounded. But members of Congress and relatives of the victims have objected to the past focus on actions by junior officers and soldiers, and questioned whether the mission was set for failure when senior commanders made decisions about the location of the austere base and what resources -- the level of personnel, types of weapons, intelligence resources and materials for building defenses -- would be assigned to the post. The new inquiry, ordered by Gen. David H. Petraeus, commander of U.S. forces in the Middle East, 'will also address circumstances beyond the tactical level,' according to an official statement. In military language, 'tactical level' indicates the unit on the ground during combat, meaning this inquiry will examine senior leadership, including officers at headquarters in charge of the overall effort. A three-star Marine Corps officer, Lt. Gen. Richard F. Natonski, was given the task of conducting the new inquiry into the events leading to and during the battle at Wanat on July 13, 2008. Among those raising questions of command negligence has been Sen. Jim Webb, Democrat of Virginia, who, in a letter, requested that the Defense Department conduct 'an independent examination of the actions taken at each level of the chain of command.' Webb cited an unpublished study by the Combat Studies Institute at Fort Leavenworth, Kan., and statements from family members that said that the platoon leader had expressed deep concerns up his chain of command that an insurgent attack was imminent. Nevertheless, intelligence, surveillance and reconnaissance resources were withdrawn for other missions, Webb's letter said. 'This action, with a platoon deployed at high risk, is on its face incomprehensible,' Webb wrote. The platoon leader, Lt. Jonathan P. Brostrom, was killed in the attack, and his father, David P. Brostrom, a retired Army colonel, has met with Webb to discuss the battle. 'The simple fact is that my son had little if any flexibility in positioning his platoon and associated weapons systems due to prenegotiated locations that were agreed to with the district governor of Wanat,' Brostrom said in an e-mail message. 'Even if my son ignored these agreements, he did not have the manpower to occupy higher ground and accomplish the mission at hand.' Military officers have said that a local Afghan police chief and another district leader provided assistance to about 200 Taliban militants who carried out the attack on the U.S. and Afghan force, which was just a third their size. 