NEW YORK RESPONSE: Passengers on the New York subway system were greeted yesterday morning with announcements warning that anyone with backpacks or large packages were liable to be searched.
Police with loudspeakers warned people of the new measures and erected notices saying: "Backpacks, other containers subject to inspection."
This is the first time that random searches have been attempted at the subway system's 468 stations, some of which have several entrances and exits. The move has drawn protests from the New York Civil Liberties Union but many passengers seemed resigned to the need for extra security.
At some outlying stations, police checked the bags of every fifth person but in Manhattan this was not possible.
Most of the 4.5 million passengers using the New York subway daily carry shopping bags, briefcases, computer bags, backpacks or suitcases, and most passed through bustling and crowded centres like Grand Central without being stopped.
Since the first bombings in London this month, there has been a noticeable increase in the number of armed police on subway platforms, sometimes backed by National Guard soldiers armed with automatic rifles.
The announcement of the new measures was made jointly by mayor Michael Bloomberg and police commissioner Raymond Kelly on Thursday. "We live in a world where sadly these types of security measures are necessary," Mr Bloomberg said.
Mr Kelly said police may also check the bags of passengers on buses and ferries. Transit system passengers who refused to be searched would not be allowed to proceed, he said. He promised that police would not single out people for their ethnicity. "No racial profiling will be allowed," he said.
NY Civil Liberties Union executive director Donna Lieberman said: "The plan is not workable and will not make New Yorkers more secure but will inconvenience them as police go about finding a needle in a haystack."
Christopher Dunn, also of the union, said the introduction of random searches without suspicion was troubling and "contrary to our most basic constitutional values".
The US Supreme Court has ruled against random searches on the basis of invasion of privacy, once overturning the drugs conviction of a person on a bus whose bag was checked at random by an officer. However, Boston police conducted snap searches at transit centres during last year's National Democratic Convention.
The explosions in London have palpably increased the sense of dread in New York that a similar attack was inevitable.