Security concerns will prevent the president from visiting his father’s ancestral village on his first official trip to Kenya.Shortly after arriving at his hotel on Friday, the president gathered in the hotel restaurant with about three dozen relatives. Obama sat in the middle of two long tables, with his step-grandmother, known as Mama Sarah, seated to his right and his half-sister, Auma Obama, a close confidante, seated to his left. The two shared a warm embrace when Auma Obama met Air Force One at the airport here late Friday. Obama is making his first official trip to Kenya as president, but security concerns prevent him from traveling to his father’s village to meet with family members. First lady Michelle Obama and the president’s daughters did not accompany him on the trip.