US warns that terrorists may pose as 'vagrants'

WASHINGTON -- Asking for increased vigilance, the government is warning that terrorists may pose as ''vagrants" to conduct surveillance of buildings and mass transit stations to plot attacks.

''In light of the recent bombings in London, it is crucial that police, fire, and emergency medical personnel take notice of their surroundings and be aware of 'vagrants' who seem out of place or unfamiliar," said an e-mail sent to some federal employees in Washington by the US Attorney's office.

It is based on a State Department report issued last week; the department had no comment yesterday.

The warning is similar to one issued by the FBI before July 4, 2004, that said terrorists may attempt surveillance disguised as homeless people, shoeshiners, street vendors, or street sweepers.

The e-mail stressed that there is no threat of an attack and that the warning is intended to be ''informative, not alarming."

The message noted a recent incident in Somerville, in which a police officer became suspicious about someone who seemed like a street person. The officer questioned the man and found he had a passport from a ''country of interest" -- typically a Middle Eastern or South Asian nation -- and a checkbook with a questionable address, the e-mail said. A probe is continuing, the e-mail added.

Somerville city spokesman Mark Horan said the incident occurred in early July, when the man walked back and forth in front of the Social Security office in Davis Square and kept looking in the windows. He was evasive about what he was doing but wasn't arrested. Police passed the information on to the FBI, Horan said.