CAMP RED CLOUD, South Korea — Reports of suicide bombers, mass casualties and general mayhem kept some of the key players in a five-base anti-terror exercise awake around the clock this week.

"Intelligence reports" began coming last week that third-party nationals were poised to strike at U.S. Army Garrison-Red Cloud.

On Thursday, the first terror strikes began at camps Red Cloud, Casey, Hovey, Stanley and Castle.

"In some cases, vehicles self-detonated. In other cases, we’d have a gunfight, with us having to simulate shooting occupants trying to enter the base," said Doug Atwater, director of plans, mobilization, training and security for the garrison, also known as Area I.

The multiple-attack scenario, planned by U.S. Forces Korea’s J-34 anti-terrorism section, is more representative of what a well-organized terrorist network could do than smaller exercises are, Atwater said.

As of Thursday afternoon, exercise actors had driven up to base gates with vehicle-borne bombs four times. Other actions produced mass casualties and emergency medical responses. More attacks were expected, followed by a review Friday.

The garrison has been adding resources with such a scenario in mind for almost two years, Atwater said.

Area I renovated its installation operations center to make room for more technical personnel. It also updated emergency equipment and held meetings with 2nd Infantry Division officials on coordination during terror attacks and natural disasters, Atwater said.