The deceased Americans were identified as Victor Lynn Lovelady and Gordon Lee Rowan, the official said, speaking on condition of anonymity because he wasn't authorized to speak publicly about the matter.
British quartet Lee Westwood, David Lynn, Matthew Blackey and Alastair Forsyth, who claimed a share of second at last week's South African Open, are in a large group of players on four under par.
The Great Britain team will consist of the same five riders who triumphed in King's Lynn, with Harris joined by Scott Nicholls, Lee Richardson, Simon Stead and Tai Woffinden, plus Danny King as cover.