Police presence is up around the United States following last week's decision to raise the terrorist threat alert level from elevated to high. But the increase in security has also heightened public anxiety.
Increased vigilance can result in numerous false alarms. On Thursday alone, two New York City bridges were closed for a time as police investigated suspicious activity. In suburban Atlanta, authorities evacuated a high school after they discovered a suspicious device in a hallway.
In Washington, tourists were startled at the sight of vehicle mounted anti-aircraft missiles pointed skyward.
The recent warnings of a possible terrorist attack have put Americans on edge. Homeland Security chief Tom Ridge briefed members of Congress on the threat Thursday and Republican Senator Kay Bailey Hutchison says there are numerous potential targets.
"I think every American needs to be very vigilant, particularly urban areas, particularly big buildings," she said. "Those are some of the general things that we are getting. Buildings that have a particular international significance, like our United States Capitol [which houses Congress]."
Opposition Democrats meanwhile are urging President Bush to set aside more money in this year's federal budget to help local cities and towns bear the cost of homeland security.
"The first responders to any terrorist crisis in America will be our policemen, our firefighters and our medical personnel. We have not provided them the resources they need to defend America," said Senator Richard Durbin of Illinois.
Local officials from around the country have come to Washington for press for homeland security aid. "In my city we have a deficit of one million dollars because of homeland security requirements that the federal government has not reimbursed us for and we are the most active port and crossing on the Canadian border," said Maryann Mahaffey is a member of the city council in Detroit.
Also Thursday, the FBI issued a new warning to a wide range of industries to check for possible terrorist infiltrators among their employees. Authorities are particularly concerned about companies involved in telecommunications, energy and heavy industry who could become prey to an attack.
Despite the heightened state of alert, Attorney General John Ashcroft told the Associated Press that the United States is making what he called "monumental progress" against terrorist around the world.
That may be true but a new public opinion poll suggests Americans are becoming increasingly jittery about security at home. A CBS News-New York Times poll found that 82 percent of those surveyed in the northeastern United States believe a terrorist attack is likely in the next few months.