U.S. President Barack Obama has vowed that Americans "will not cower in fear" following the failed car-bomb attack in New York's Times Square on Saturday.
He said the incident was a "sobering reminder of the times in which we live" and vowed that justice would be done.
Faisal Shahzad, a 30-year-old Pakistan-born U.S. citizen, is due to appear at a court in Manhattan later. Officials say he will be charged with terrorism.
"Justice will be done and we will continue to do everything in our power to protect the American people."
Mr Obama said "hundreds of lives" might have been saved by the vigilance and quick action of citizens and the authorities in New York.
"We know that the aim of those who try to carry out those attacks is to force us to live in fear," he said.
"But as Americans and as a nation, we will not be terrorized. We will not cower in fear. We will not be intimidated."
Earlier, law enforcement officials said Mr Shahzad had made statements implicating himself and told them he had acted alone.
"He's admitted to buying the truck, putting together the devices, putting them in the truck, leaving the truck there and leaving the scene," one unnamed source told the Reuters news agency.
"He's claimed to have acted alone. He did admit to all the charges."
The FBI searched Mr Shahzad's home in Bridgeport, Connecticut, on Tuesday morning and removed several plastic bags filled.
Investigators are also looking into Mr Shahzad's activities during a recent trip to Pakistan, and are trying to ascertain Whether he or others who might have been involved were in contact with people or groups overseas.
Sources told the BBC that Mr Shahzad was in Karachi for at least a month last year and other reports say he spent some months in the frontier city of Peshawar, close to Taliban strongholds and training grounds.
Pakistani Interior Minister Rehman Malik has pledged to assist the U.S. in identifying those responsible and bringing them to justice.
On Sunday, the Pakistani Taliban said it was responsible for the failed bombing attempt and it threatened suicide attacks on U.S. cities.
But the BBC's Orla Guerin in Islamabad says there is no proof and many experts doubt they have the capacity to strike inside the U.S..
'Significant fireball'
The car containing a bomb made from fertilizers, fireworks, petrol and propane gas tanks was left in Times Square on Saturday evening.
The 1993 Nissan Pathfinder was parked with its engine running and hazard lights flashing.
The bomb was discovered and dismantled before it could explode, after a street-vendor noticed smoke coming from the vehicle and Alerted police.
Mr Holder told an earlier news conference that investigators were pursuing several leads, adding: "We will not rest until we have brought everyone responsible to justice."
He said the attempted car bombing "would have been a deadly attack had it been successful".
"It's clear that the intent behind this terrorist act was to kill Americans."
Times Square was packed with tourists and theatregoers when the alarm was raised.
Police evacuated a wide area of the district and closed subway lines, while a controlled explosion was carried out.
Officials said the bomb was crude, but could have sparked a "significant fireball" and shrapnel sprayed with enough force to kill pedestrians and knock out windows.
Investigators initially focused on a man who was seen on one video walking away from the area where the car was parked. He looked over his shoulder at least twice and pulled off a shirt, revealing a red T-shirt underneath.
New York's police commissioner said investigators still wanted to speak to the man, but acknowledged that he might not be connected to the bombing attempt.
He was arrested at John F Kennedy airport on Monday on board a plane.
Police detained him shortly before the plane Dubai-bound was due to take off, and U.S. Attorney General Eric Holder says he will be charged with an act of terrorism and attempting to use a weapon of mass destruction.
He is believed to have recently bought the SUV that was found loaded with an improvised explosive device in Times Square.
Investigators say Mr Shahzad, from Connecticut, has told them he was acting alone and had no connections with foreign militant groups.
Reports from Pakistan say Mr Shahzad's father-in-law and another associate of the suspect have been arrested in the port city of Karachi - although there has no been official confirmation.
Pakistan trip
Mr Obama said the FBI and police had "all the tools they need to learn everything we can".
"That includes what, if any connection, this individual has to terrorist groups," he said in a speech to the Business Council in Washington.
RELATED TAGS : HOME INSURANCE, BUSINESS , FOREX , REALESTATE , MARKETING , AUTOMOBILES , CURRENCY’S , INVESTING IDEAS , SHARES , BUSINESS INSURANCE , LIFE INSURANCE, SAVE TO MONEY
