In a stealthy seaside assault in Somalia, U.S. special forces on Saturday struck out against Islamic extremists who have carried out terrorist attacks in East Africa, before eventually aborting the mission to capture a leading terrorist suspect linked to last month's Nairobi shopping mall attack after a fierce firefight. A U.S. Navy SEAL team swam ashore near a town in southern Somalia before militants of the al-Qaeda-linked terrorist group al-Shabab rose for dawn prayers. The raid on a house in the town of Barawe targeted a specific al-Qaeda suspect related to the mall attack, but the operation did not get...