Complex sentence: In the pursuit, the 33rd would continue to be punished by the U.S. forces losing approximately 40 percent, or 600, of its 1,500 men were killed in the siege and its aftermath.
Split into simpler sentences: In the pursuit, the 33rd would continue to be punished by the U.S. forces. Approximately 40 percent, or 600, of its 1,500 men were killed in the siege and its aftermath.