U.S. Customs and Border Protection plans to select four to eight firms in the coming weeks to build the prototypes for President Donald Trump’s much-touted border wall, Ronald Vitiello, the agency’s acting deputy commissioner, said Tuesday.The administration’s update on its plans for the wall comes amid delays in the bidding process and a seeming lack of political will to fund a continuous barrier along the 2,000-mile Mexico border.The prototypes -- including a reinforced concrete barrier wall as well as one made of an alternative material with see-through capability -- will be built in San Diego.Firms are expected to complete construction by September, within 30 days of their selection, Vitiello said.More than 200 companies responded to the federal government’s two requests for proposals for the border wall in March.