It was part of an exercise for officials at the highest level of the U.S. government, including members of the National Security and Homeland Security Councils.
What made "National Level Exercise 2009" different from previous training events, is that it focused "exclusively" on preventing a terror attack - as opposed to responding to and recovering from one.
A statement from FEMA, the Federal Emergency Management Agency, says today's exercise, part of a week-long program, was mandated by Congress to give top officials realistic experience in handling the threat of a catastrophic crisis.
Today's scenario according to FEMA, began with a terrorist event outside the U.S. It then became the responsibility of Mr. Obama and other top American officials to thwart efforts by the terrorists to enter the U.S. and carry out additional attacks.
Aside from federal departments and agencies, state and local authorities were taking part in the exercise in addition to officials from Australia, Canada, Mexico and the United Kingdom.
The exercise is deemed by FEMA to be "an important component of national preparedness." The White House and other parts of the government will be evaluated on such capabilities as intelligence sharing, counter-terrorism, border security, public notification and international coordination.
FEMA says the terrorism prevention efforts in today's exercise would be allowed "to proceed to a logical end – successful or not."