I first heard this on ABC Radio ... that security teams of some sort are out in the streets of Boston with some sort of radiation detection equipment, apparently on tip someone may be trying to detonate a dirty bomb in the city. Then saw it on Drudge: talking about Massachusetts Emergency Mgt. Agency "in the bunker."
On edit: Boston Globe now has story.
http://www.boston.com/news/local/massachusetts/articles/2005/01/19/search_underway_for_six_who_may_pose_terrorist_threat_to_boston?mode=PFSearch underway for six who may pose terrorist threat to Boston
"The FBI has triggered a massive manhunt for six people -- four Chinese and two Iraqis -- who may pose a terrorist threat to the city of Boston, law enforcement officials briefed on the threat said today.
"The six are suspected of having come into the United States from Mexico, and may have headed to New York and then to Boston, the target of a planned attack that could involve a lethal substance, possibly chemical or biological or explosive, three law enforcement officials briefed on the threat said.
"The tip about the threat was given to the FBI by only one person, the officials said, and it had not been corroborated as of this afternoon.
"... The state Emergency Management Agency has partially activated its emergency response team, with representatives from the Department of Public Health, the Department of Environmental Protection, and the State Police now holed up in the emergency bunker in Framingham until the threat has passed."