The US authorities investigating the attempted bombing in New York's Times Square have arrested three men during searches in three US states.
Homes in New York, New Jersey and Massachusetts were searched early on Thursday.
Justice department spokesman Dean Boyd said the men were being held over alleged immigration violations.
Pakistani-born US citizen Faisal Shazhad, 30, has already been charged with the attempted bombing on 1 May.
Authorities say Mr Shahzad, who lived in Connecticut prior to the bombing attempt, has waived his US legal rights and is co-operating with federal officials.
A law enforcement official told the Associated Press news agency that two of the men taken into custody from a house near Boston, Massachusetts, were from Pakistan.
The official said one of the men had been arrested because he had overstayed his visa.
A second man had already been awaiting a ruling from an immigration court hearing on whether he would be removed from the country.
'No immediate threat'
In its statement on the latest arrests, the FBI said it could "confirm that search warrants have been executed in several locations in the Northeast in connection with the investigation into the attempted Times Square bombing".
It added: "This search is the product of evidence that has been gathered in the investigation subsequent to the attempted Times Square bombing and [does] not relate to any known immediate threat to the public or active plot against the United States."The FBI is carrying out search warrants at locations around Boston, Massachusetts, Cherry Hill and Camden in New Jersey, and Centerreach and Shirley in New York.
Police have also cordoned off a house in Watertown, Massachusetts, a Boston suburb.
Vinny Lacerra, who lives across the street from the house concerned, said he had heard someone yell "FBI! Put your hands up!" at 0600 local time (1100 GMT).
Mr Lacerra told the Associated Press he had seen 15 to 20 FBI agents with their guns drawn outside the house.
He then saw a man taken out of the building in handcuffs about 15 minutes later.
An agent from Immigration and Customs Enforcement is reported to have been among those outside the Watertown house.
Agents have also recovered a Honda car from a Mobil petrol station on Harvard Street in Brookline, Massachusetts, another suburb of Boston.
The vehicle is reportedly linked to the address in Watertown, Massachusetts.
Justice department spokesman Dean Boyd said the searches were the result of evidence collected during a 13-day investigation.
Mr Shazhad has told officials he acted alone. But investigators have uncovered a possible link over the attempted bombing to the Pakistani Taliban and a Kashmiri Islamist group.
The Pakistani Taliban claimed responsibility for the failed attempt in Times Square. If this claim is true, the attempt would be the group's first act in the United States.
Source : bbc