Complex sentence: On 17 October 2013, the South Korean military asked the Pentagon to provide information on the THAAD system concerning prices and capabilities as part of efforts to strengthen defenses against North Korean ballistic missiles.
Split into simpler sentences: On 17 October 2013, the South Korean military asked the Pentagon to provide information on the THAAD system. Information of the system concerned prices and capabilities as part of efforts to strengthen defenses against North Korean ballistic missiles.