The 1st Marine Provisional Brigade, in conjunction with Task Force Hill, mounted a massive attack on Cloverleaf Hill and Obong-ni on August 17.
The offensive began at 08:00 on August 17, with US forces unleashing all heavy weapons available to them against the KPA positions; artillery, mortars, M26 Pershing tanks and airstrikes.

At first, tenacious KPA defense halted the Marines who responded with artillery, raking Cloverleaf Hill.
Heavy indirect fire forced the KPA out of their positions before the Marines and Task Force Hill eventually overwhelmed them, one hill at a time.
The Marines approached Obong-ni first, destroying resistance on the slope with an airstrike and a barrage from US tanks, but strong resistance caused heavy casualties, and they had to withdraw.
The KPA 18th Regiment, in control of the hill, mounted a disastrous counterattack in hopes of pushing the Marines back.
The division's tactics of cutting off supplies and relying on surprise, which had provided them so much success up to this point, failed in the face of massive US numerical superiority.

By nightfall on August 18, KPA 4th Division had been annihilated; huge numbers of deserters had weakened its numbers during the fight, but by that time, Obong-ni and Cloverleaf Hill had been retaken by the US forces.
Scattered groups of KPA soldiers fled back across the Naktong, pursued by American planes and artillery fire.
The next day, the remains of 4th Division had withdrawn across the river.
In their hasty retreat, they left a large number of artillery pieces and equipment behind which the Americans later pressed into service.
The 1st Marine Provisional Brigade, in conjunction with Task Force Hill, mounted a massive attack on Cloverleaf Hill and Obong-ni on August 17. The offensive began at 08:00 on August 17, with US forces unleashing all heavy weapons available to them against the KPA positions; artillery, mortars, M26 Pershing tanks and airstrikes.
At first, tenacious KPA defense halted the Marines who responded with artillery, raking Cloverleaf Hill. Heavy indirect fire forced the KPA out of their positions before the Marines and Task Force Hill eventually overwhelmed them, one hill at a time. The Marines approached Obong-ni first, destroying resistance on the slope with an airstrike and a barrage from US tanks, but strong resistance caused heavy casualties, and they had to withdraw. The KPA 18th Regiment, in control of the hill, mounted a disastrous counterattack in hopes of pushing the Marines back. The division's tactics of cutting off supplies and relying on surprise, which had provided them so much success up to this point, failed in the face of massive US numerical superiority.
By nightfall on August 18, KPA 4th Division had been annihilated; huge numbers of deserters had weakened its numbers during the fight, but by that time, Obong-ni and Cloverleaf Hill had been retaken by the US forces. Scattered groups of KPA soldiers fled back across the Naktong, pursued by American planes and artillery fire. The next day, the remains of 4th Division had withdrawn across the river. In their hasty retreat, they left a large number of artillery pieces and equipment behind which the Americans later pressed into service.
First Battle of Naktong Bulge