Pentagon chief heads to Asian summit as nations fret over S. China Sea

The guided missile destroyer USS William P. Lawrence transits the Philippine Sea in March.

Washington (AFP) - US Defense Secretary Ashton Carter will depart Tuesday for an Asian security summit in Singapore, where Beijing's military expansion across the South China Sea likely will once again dominate discussions.

Regional neighbors are fretting over what they see as China's expansionism as it rushes to exert sovereignty over the waterway, a major global shipping route believed to be home to large oil and gas reserves.