Bulletin: Terrorists On School Buses?

Members of extremist groups have signed up as school bus drivers in the United States, counterterror officials said Friday, in a cautionary bulletin to police. An FBI spokesman said "parents and children have nothing to fear."

Asked about the alert notice, the FBI's Rich Kolko said "there are no threats, no plots and no history leading us to believe there is any reason for concern," although law enforcement agencies around the country were asked to watch out for kids' safety.

The bulletin, which was sent Friday, did not say how often foreign extremists have sought to acquire licenses to drive school buses, or where.

But security sources tell CBS News correspondent Bob Orr that over a period of time a number of school districts have been reporting an increase in the number of foreign nationals seeking bus driver jobs.

The bulletin says some foreign nationals "of investigative interest" have been able to purchase buses and acquire licenses, sources tell Orr.

Most of the attempts to acquire licenses appear to be legitimate, but there have been a few instances where "abnormal behavior was noted."

Foreigners under recent investigation include "some with ties to extremist groups" who have been able to "purchase buses and acquire licenses," the bulletin says.

But Homeland Security and the FBI "have no information indicating these individuals are involved in a terrorist plot against the homeland," it says. The memo also notes: "Most attempts by foreign nationals in the United States to acquire school bus licenses to drive them are legitimate."

Security officials stree that this is the latest in a series of "routine alerts" issued "out of an abundance of caution," Orr reports.

But officials tell Orr they cannot ignore the fact that large vehicles, like buses, have been used overseas to deliver improvised explosive devices.

One counterterror official, who spoke on condition of anonymity because of the sensitivity of the issue, said it was likely that the foreigners investigated were merely employed as bus drivers, and did not intend to use them as part of any terror plot.