PORTLAND, Ore. - Conspiracy theorists, most of them on the Internet, are saying a exercise currently under way by the Oregon National Guard is a prelude to a nuclear attack on Portland.

Oregon National Guard officials say the exercise, called Operation Noble Resolve, is a drill to help break in new computer programs designed to coordinate state, federal and local authorities in case of a natural disaster, terrorist attack or other emergency.

"Some of the simulations we've gone through had a simulated 7.2 earthquake centered 20 miles east of Portland," Major Verl Miller with the Oregon National Guard said.

Miller said the drill is also testing how the Oregon National Guard itself would work to react to a major emergency in concert with local and federal authorities.

Internet conspiracy theorists say the drill is part of a government plan to attack the city with a nuclear weapon and then establish martial law.

Operation Noble Reserve is scheduled to conclude August 24.