By Edith Honan
NEW YORK (Reuters) - Federal anti-terrorism officials alerted local police departments around the United States about how to track evidence of bomb-making after authorities raided New York homes on Monday in an apparent search for homemade explosives.
The FBI and the Department of Homeland Security advised the police to look for burn marks typically found on suspects of a particular kind of bomb-making. The note was issued following searches of at least three apartments where a man suspected of sympathizing with al Qaeda had visited.
A U.S. Justice Department spokesman said on Tuesday the advisory was a direct result of Monday's raids, carried out by a joint anti-terrorism task force that included New York police and the Federal Bureau of Investigation. Authorities declined to say whether anyone was arrested.
The raids rattled people in Queens, the ethnically diverse borough across the East River from Manhattan, and reminded New Yorkers their city remains a target eight years after the September 11 attacks.
"We believe it is prudent to share information with our state and local partners about the variety of domestically available materials that could be used to create homemade explosives," the federal agencies said in a statement.
New York police and the FBI have provided few details about the raids. Witnesses described an operation in which dozens of heavily armed FBI agents arrived in a phalanx of unmarked vehicles and stormed the building in the early morning.
A federal law enforcement official said three search warrants had been executed.
Members of Congress briefed by the FBI said there was no imminent danger. Charles Schumer, a U.S. Senator from New York who was among those briefed, said the action was "preventive."
"In the absence of any information, it is understandable that people are anxious," New York City Councilman John Liu, who represents the neighborhood where the raids took place, said in a statement. "People are fully cooperating with the authorities."
(Editing by Daniel Trotta and Philip Barbara)
