Mr Rogers, who chairs the US Strategic Forces Subcommittee which oversees missile defence, did not say which west coast locations were under consideration but revealed several sites were “competing” for the missile defence installations…

He added: “It’s just a matter of the location, and the Missile Defence Agency making a recommendation as to which site meets their criteria for location, but also the environmental impact.”

Mr Rogers (Republican) and Mr Smith (Democrat) both said the number of THAAD systems that may ultimately be deployed had yet to be determined.