WASHINGTON — Fourteen U.S. citizens have been charged with attempting to join al-Shabab, a Somali-based terrorist group linked to al-Qaida, law enforcement officials told NBC News. The charges were due to be formally announced at a news conference at noon ET at the Justice Department, NBC reported. The 14 people include 12 from Minnesota, one from Alabama and one from California, the officials said. Al-Shabab is Somalia's most-feared militant group. The group recently claimed responsibility for bombing two sites in Uganda where people were watching a soccer World Cup game on television, killing 76 people. Al-Shabab said the blasts were...