"Does it bother you that you're going to have people looking through your bag to get on the subway?" CBS News Correspondent Jim Axelrod asked one commuter.
"Sure it does," was the response, "but at the same time, if someone is bringing in a backpack like these terrorists are, then I guess they have to wait and see."
said to be wearing a thick coat at a London subway station Friday, a day after the city was hit by a second wave of terror attacks in two weeks.
"[Friday's London incident] shows that we all live in a different world since Sept. 11, and that's one of the reasons why we've put in place these random bag searches," said New York City Police Commissioner Ray Kelly on CBS News' The Early Show.
The inspections started on a small scale Thursday afternoon in Manhattan and were expanded during Friday morning's rush hour.
"Obviously, the events in London show they are continuing to focus on transit systems and we think this is a proven measure, a common sense measure to put in place," said Kelly.
The New York Civil Liberties Union was to monitor Friday's developments before deciding what action, if any, to take.
"It violates our right to privacy when the police search us, search our belongings, when we haven't done anything wrong," Donna Lieberman of the NYCLU told CBS News.
"I'm not against it," Ian Compton, 35, a computer consultant, said at Grand Central Terminal. "I think any measures for safety that aren't terribly intrusive are worth doing."
As police across the New York City region stepped up transit security in response to a new round of attacks in London, a man with a record involving a pipe bomb was arrested with a weapons cache outside a Long Island commuter train station.