U.S. implements emergency plans

By CNN's Henry Schuster

(CNN) -- The U.S. Federal Emergency Management Agency (FEMA) says it is implementing an operations plan that was prepared for such events as Tuesday's terrorist attacks.

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In a written release, FEMA said it is working closely with other U.S. federal agencies, particularly the FBI, which leads the investigation.

Under a previously agreed-upon plan, the Justice Department is responsible for crisis management.

Meanwhile, the military command that would respond to assist domestically said it has not yet been asked to move any troops.

"At this time, we have not made any decisions nor been directed to move troops," said a spokesman at Fort MacPherson in Atlanta. "We're like everyone else, we're in the assessment phase."

The Army's Forces Command is charged with the military response to weapons of mass destruction on U.S. soil.

The spokesman said that security at the base is being re-evaluated and appropriate measures are being taken, but "this in no way disrupts our ability to respond."