Further, plans call for a shifting away from a network of tower-mounted sensors and surveillance gear, The Washington Post reports.

Technical problems discovered in a 28-mile pilot project south of Tucson dictated a change in plans, Homeland Security officials told a U.S. House subcommittee.

The delay marked a major setback for what President Bush, in May, 2006, called "the most technologically advanced border security initiative in American history." This was to be a key component of his proposed overhaul of U.S. immigration policies.

But, officials disclosed new troubles that will require a redesign, and said the first phase will not be completed until near the end of the next president's first term.

The problems included Boeing's use, in the early work, of inappropriate commercial software to integrate data related to illicit border-crossings, it was reported.