HANOI :Vietnamese and Americans firms have signed a series of deals on energy and minerals during a visit to the United States by Vietnam's trade minister, state media and one of the firms said on Friday. Vietnamese companies are in talks with U.S. firms to buy American crude oil and LNG, said state-controlled PetroVietnam Power, which is a signatory to one of the deals and has executives accompanying the minister on the trip. Vietnamese trade minister Nguyen Hong Dien is in the United States