WASHINGTON (AP) – Members of extremist groups have signed up as school bus drivers in America, 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, parts of which were read to The Associated Press, did not say how often foreign extremists have sought to acquire licenses to drive school buses, or where. It was sent Friday as part of what officials said was a routine FBI and Homeland Security Department advisory to local law enforcement.

It noted “recent suspicious activity” by foreigners who either drive school buses or are licensed to drive them, according to a counterterror official who read parts of the document to The Associated Press.

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.”

Mr. Kolko said the bulletin was sent merely as an educational tool to help local police identify and respond to any suspicious activity.

It was not immediately clear whether the extremists intended to do with the school buses. 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.