Bloomberg Cites 'Specific Threat' to N.Y. Subways

New York City and federal officials said this evening that they had received information about a specific but unconfirmed terrorist threat to the city's transit system and that the police presence in the subways would be heightened in coming days.

"This is the first time we have had a threat with this level of specificity," Mayor Michael R. Bloomberg said at a televised news conference carried live by the early-evening local news broadcasts, the New York Times reports. . But the mayor said the city was not raising its color-coded threat level from "orange," the second-highest in the system used since the terror attacks of Sept. 11, 2001, and he urged New Yorkers to continue using the subway system, as he said he would tonight and Friday morning, per his routine.

Police Commissioner Raymond Kelly did suggest that riders not bring backpacks, briefcases, baby carriages and luggage if they can do without them. Police officers were stepping up the random bag searches that began after this summer's train and bus bombings in London. Mr. Bloomberg said that undercover officers would also be deployed in subway stations and trains.

Government officials said that in the last couple of days, a C.I.A.-F.B.I. operation in Iraq had taken two people there into custody in an effort to disrupt the plot. The officials, who spoke on condition of anonymity because details are classified, said the plot appeared to involve a dozen or so people in an effort to plant explosives in the subway system around the middle of this month.

At the news conference, officials would only allude to an overseas operation and declined to provide details about detentions, saying only that they had taken place outside New York. Mr. Mershon said the threat could be "resolved in the coming days," but he did not explain what he meant.

The city has known about the threat for several days, the mayor said, but decided that making it public too soon "could have jeopardized the lives" of some investigators.

While calling the information "more specific as to target and timing" than routine threats, the mayor said that "there are lots of different pieces of information, all of which are not necessarily consistent." He also asked subway riders to report any suspicious activity or person to the police.