A look at how some federal agencies responded to the heightened terror alert warning issued Tuesday:
The Pentagon's official security condition remained at Charlie, the second-highest level on a four-tier scale. The Pentagon was at "Force Protection Condition Delta," the highest level, for weeks after last year's attack.
The military raised the security level to Delta at the base in Bahrain which is home to the U.S. Navy's 5th Fleet. Other U.S. bases overseen by Central Command, which covers the Persian Gulf, the Horn of Africa and Central Asia, boosted security to Charlie, officials said.
Security at the Pentagon and military bases worldwide already were heightened because of the Sept. 11 anniversary. On Friday, the military resumed 24-hour patrols by fighter jets over New York City and Washington.
The military planned Tuesday to deploy live anti-aircraft missiles to launchers stationed around Washington for a training exercise. Defense Secretary Donald H. Rumsfeld ordered the missiles taken to the launchers, where they could be quickly loaded and fired if needed.
The State Department issued a notice of "worldwide caution" to Americans abroad, citing the threat of more terrorist acts against U.S. interests. The warning remains in effect until Oct. 31, said State Department spokesman Richard Boucher.
Possible attacks could include suicide operations against government facilities or installations that are "identifiably American," Boucher said. And Americans could be at risk of abduction or other violent acts, Boucher said.
The government closed nine embassies and one consulate overseas on Tuesday due to fears of terrorism on the eve of the anniversary of the Sept. 11 attacks. The countries involved were Indonesia, Bahrain, Vietnam, Pakistan, Malaysia, Cambodia, Malawi, Tajikistan and United Arab Emirates.
Embassies in six countries -- Ivory Coast, Cape Verde, Oman, South Africa, Mozambique and Brunei -- were to close Wednesday for Sept. 11 commemorations.
Embassies in Ethiopia, Eritrea, Micronesia and Mauritius were to close Wednesday for local holidays.
GENERAL SERVICES ADMINISTRATION
The General Services Administration, which operates and provides security for most of the government's buildings, immediately alerted federal agencies and implemented new security procedures. The agency declined to specify changes, citing security concerns.
The Secret Service continued on a high state of alert, spokesman John Gill said. He wouldn't say whether operations were changed as a result of the higher threat.
All federal air marshals are working and the Coast Guard has increased patrols and inspections, spokesman Robert Johnson said. He said airports around the country were put on a higher alert. The Federal Aviation Agency said the alert did not force it to change its handling of the air traffic system.
Amtrak, the national passenger railroad, will put additional police officers in train stations and on platforms, spokeswoman Karina Van Veen said. She said other enhanced security measures will not be disclosed to the public.
CENTERS FOR DISEASE CONTROL AND PREVENTION
The CDC's emergency operations center in Atlanta is operating 24 hours a day, said spokesman Von Roebuck. The increased hours began on Saturday in anticipation of the Sept. 11 anniversary. The center is responsible for responding to inquiries from states and, if necessary, deploying response teams.
The Interior Department's security teams are in closer contact with the Secret Service, the U.S. Capitol Police, Washington police and the Defense Department. The heightened terror alert also means the department takes added precautions for public events, but so far there are no plans to restrict or cancel any planned activities.
The staff has been alerted to be extra cautious, said spokeswoman Sue Hensley. Tightened security into the building was implemented after last year's attacks. But two-thirds of the department's workers are outside Washington, so officials are in close contact with those field offices.
The department has been on heightened alert since Sept. 11 and does not plan any changes, said spokesman Trevor Francis.
The government's research laboratories and nuclear weapons facilities, already on high alert, were notified of the upgraded terrorist warning and directed to impose additional security measures, said Energy Department spokeswoman Jeanne Lopato. She declined to specify what additional measures were being taken.
NUCLEAR REGULATORY COMMISSION
The nation's nuclear power plants were directed to implement heightened security measures, although federal officials said they had no specific threat against any nuclear facility, said NRC spokesman William Beecher. He said that when the orange alert was issued, the NRC advised all operators of power reactors and other nuclear facilities to implement heightened security measures that were outlined last month.
Cars and trucks coming onto the sprawling federal complex will receive extra scrutiny as a result of the heightened security warning, said bureau spokeswoman Laverne Collins. All trucks parked at the bureau's loading dock will be inspected. A note will be sent to all bureau employees reminding them of emergency numbers and asking workers to be watchful for any suspicious activity.
Four locked steel cabinets containing "escape hoods" were installed in the House press gallery on Tuesday. The hoods can be pulled over people's heads, allowing them to breath in the event of a biological or chemical attack. The House has been acquiring 25,000 additional escape masks and has trained 6,410 House members and staff in their use, said Wilson Livingood, the House sergeant at arms. The Capitol has been under heightened security since Sept. 11, with all personnel passing through metal detectors and having their bags scanned, all cars checked with bomb-sniffing dogs and new security barriers present on all sides of the building to stop oncoming cars.
Customs is implementing additional security precautions, including more examination of vehicles, passengers, cargo and mail. The agency said that it does not anticipate significant increases in wait times at the nation's border as a result of the actions being taken.
ENVIRONMENTAL PROTECTION AGENCY
The EPA readied its rapid response teams in case of chemical or biological attack, put more staff on quick standby and prepared to be able to fully activate its national emergency operations center. It also advised water system operators and chemical plants to make immediate and temporary security upgrades that could include posting more guards or limiting the number of access roads to a site.
The Agriculture Department used its emergency phone network to alert employees of the changed threat level, putting meat inspectors and forest rangers alike on the lookout for anything suspicious.
The Education Department has done a lot with schools to help with crisis plans, a byproduct of school shootings in the past several years, said Dan Langan, Education Department spokesman.
The Postal Service is not closing any facilities or sealing off mailboxes. Employees have been told to be alert for anything suspicious.
The Treasury Department, which includes Customs and Alcohol, Tobacco and Firearms and oversees the nation's financial system, has taken extra precautions in light of the new threat level. The department's law enforcement bureaus have taken steps to increase scrutiny at the borders, maintain the integrity of financial institutions and increase the level of vigilance with respect to all law enforcement duties and responsibilities.
FEDERAL EMERGENCY MANAGEMENT AGENCY
The agency activated its Emergency Support Team Monday in connection with the Sept. 11 anniversary. It has increased security by more carefully screening guests and visitors, and has reminded employees to be on higher alert.
The Federal Reserve Board will continue to have the appropriate level of security measures in place, and is closely monitoring the situation.
IMMIGRATION AND NATURALIZATION SERVICE
The Immigration and Naturalization Service plans to ask additional questions of people seeking admission to the United States and send more people and cars to secondary inspections, where more in-depth questioning and searches are conducted. Fingerprinting and photographing of visitors from Iraq, Iran, Syria, Libya and Sudan, as well as certain other foreigners, will begin. The Justice Department has not named which ports of entry are involved.
HEALTH AND HUMAN SERVICES
Security at the Department of Health and Human Services headquarters was tightened, with closer scrutiny of cars parked in the garage and more security personnel on site. Officials in charge of deploying medical supplies and personnel, always ready to go, were notified to the change in alert status.
Supreme Court officials refused to discuss security at the high court, but there have been increased officer patrols on the court grounds and inside the building in recent days. The U.S. Marshals Service also would not divulge any security changes at federal courts. Those courts have also been under tighter security, with restricted parking around buildings, identification checks and metal detectors at court entrances and an increased officer presence.
Pipeline companies had been given guidance beforehand on new security procedures if the alert level was changed, said Benjamin Cooper, president of the Association of Oil Pipe Lines. The electric power industry and operators of power plants and transmission grids were informed immediately of the change in alert levels through the private National Electric Reliability Council.