The federal building in Dallas is open but under a state of alert. Some office buildings in the region have closed for the day.Under a first-ever mandate from the FAA, all airports are grounded. Dallas-Ft. Worth International Airport's Department of Public Safety has the facility under the highest security alert.

Meanwhile, the Ft. Worth BOMA chapter has issued a heightened alert warning for all building owners. The chapter is recommending that all security plans immediately be rolled out. "This is a precautionary note," says the directive. "We do not know how widespread this will become. Be aware and make appropriate security plans." The BOMA directive is being supported by the Ft. Worth Fire Department, an official said.

In a prepared statement, BOMA International says, "Due to what appears to be terrorist attacks this morning in NYC at the World Trade Center, and now in Washington, DC at the Pentagon and elsewhere, BOMA International's offices will close today. Staff are concerned about family, friends and their ability to get home should the situation worsen. Road, airport and metro closings have already been announced. Vice presidents will be responsible for contacting their staff regarding plans to open the office tomorrow.