The Eighth Army, commanded by Lieutenant General Walton Walker, began preparing a counteroffensive, the first conducted by the UN in the war, for August. It would kick off with an attack by the US reserve units on the Masan area to secure Chinju, followed by a larger general push to the Kum River in the middle of the month. One of Walker's goals was to break up a suspected massing of KPA troops near the Taegu area by forcing the diversion of some KPA units southward. On August 6, the Eighth Army issued the operational directive for the attack by "Task Force Kean", named for the US 25th Infantry Division commander, William B. Kean. "Task Force Kean" consisted of the 25th Division, less the 27th Infantry Regiment and a field artillery battalion, plus the 5th Regimental Combat Team and the 1st Provisional Marine Brigade attached — a force of about 20,000 men. The plan of attack required the force to move west from positions held near Masan, seize the Chinju Pass, and secure the line as far as the Nam River. However, the offensive relied on the arrival of the entire 2nd Infantry Division, as well as three more battalions of American tanks.