In the new poll, more than twice as many now say terrorism is the most important problem facing the U.S. than did so last month. Fifteen percent cited terrorism as the most important issue, compared to just six percent last month.
Terrorism is second to the war in Iraq, which is seen as the top problem by Americans at 22 percent, the poll finds.
Meanwhile, in New York and other big cities, commuters were fuming Friday after learning of Homeland Security Secretary Michael Chertoff's remarks that cities will have to pay to protect trains and buses because airplanes are a higher priority.
The federal government is temporarily footing the extra $1 million a week New York is spending to move police officers from around the city into the transit system in the wake of the London terror attacks.
But in the long term, cities will be largely on their own when it comes to securing trains and buses, Chertoff told The Associated Press on Thursday, explaining that airplanes are a higher priority for Washington.
"Michael Chertoff is a very smart guy, but I couldn't disagree more," New York Mayor Michael Bloomberg said.
The free subway tabloid amNew York summed up his comments Friday: "Pay Your Own Way," the headline declared over a close-up of a grim-faced Chertoff.
"I think it stinks," psychologist David Amarel said as he boarded the subway in Brooklyn. Like many New Yorkers, he said he felt the federal government's foreign policy makes the city a target, so the government should assume responsibility for its security.
Chertoff told the AP on Thursday that "A fully loaded airplane with jet fuel, a commercial airliner, has the capacity to kill 3,000 people. A bomb in a subway car may kill 30 people. When you start to think about your priorities, you're going to think about making sure you don't have a catastrophic thing first."
New York's bus and subway system, which carries 7 million riders a day, has been the target over the years of at least two alleged attempted terrorist attacks, both of which were stopped before they could be carried out.
"It's because New York symbolizes America, in other people's eyes anyway," said Sayyed Nabaweyyah, a retired teacher commuting into Manhattan.
In San Francisco, Bay Area Rapid Transit spokesman Linton Johnson said officials were "very disappointed" and "completely stunned" by Chertoff's comments.
BART carries 310,000 passengers a day, nearly twice as many as the San Francisco Bay area's three major airports combined, Johnson said.
"A terrorist can affect more people on a train," he said. "One fully loaded BART train holds more people than a 747."
Although there is an increased focus on security for U.S. mass transit systems due to the London bombings, CBS News Correspondent Jim Stewart reports that right now U.S. officials don't have anything that links that attack back to the United States.
However, Stewart also notes that law enforcement officials are looking into the time that a chemist who was arrested in Cairo on Friday spent in the U.S. Magdy Mahmoud Mustafa el-Nashar, 33, studied biochemistry for about five months at North Carolina State University about five years ago.