The surviving suspect in the Boston Marathon bombings has been charged with using a weapon of mass destruction, the US Department of Justice says.
Dzhokhar Tsarnaev, who was charged in hospital, could face the death penalty.
A White House spokesman has said Mr Tsarnaev will not be treated as an "enemy combatant", as suggested by some Republican members of Congress.
The twin bombs near the finishing line of last Monday's marathon killed three people, and injured more than 200.
Dzhokhar Tsarnaev, 19, was captured on Friday evening after a huge manhunt during which his elder brother and suspected fellow bomber, Tamerlan Tsarnaev, 26, died.
He has been unable to speak because of a throat wound, though he has reportedly responded to questions in writing.
Citing court papers, the New York Times reported he was advised of his rights and the charges against him by a magistrate during the bedside arraignment.
As well as a count of using a weapon of mass destruction, Dzhokhar Tsarnaev faces one count of malicious destruction of property resulting in death, the Department of Justice said in a statement.
In addition to federal charges, prosecutors for the state of Massachusetts, which does not have the death penalty, could file their own.
"He will not be treated as an enemy combatant," said White House spokesman Jay Carney.
"We will prosecute this terrorist through our civilian system of justice."
The city of Boston observed a moment of silence for the victims at 14:50 local time (18:50 GMT), exactly a week after the attack.
'I did that'
A criminal complaint by the FBI related to the charge sheet outlines the sequence of events leading up to the explosions at the finish line of the marathon and the subsequent clashes with the police three days later.
The document says the brothers were seen with explosives at the marathon - with the same type of device thrown at officers chasing them.
It also said one of the bombers told a carjacking victim: "Did you hear about the Boston explosion? I did that."
Dzhokhar Tsarnaev is being treated in Boston's Beth Israel Deaconess Medical Center for injuries he sustained before his capture, when he was found hiding in a boat in the back yard of a house in Watertown, a suburb of Boston.
The FBI complaint said he was found with "apparent gunshot wounds to the head, neck, legs and hand".
The hospital said on Monday that his condition remained serious. The charges against him were unsealed in his hospital room, in what was described as an initial court appearance.
Also on Monday, a private funeral was being held for 29-year-old restaurant worker Krystle Campbell, who was killed at the marathon finish line after going to watch the race with a friend.
The BBC's Richard Fenton-Smith, who was outside the church in Medford, north-west of Boston, said the whole town came to a standstill for the service, with many of the hundreds of mourners arriving in coaches.
Members of the public lined the route to the chapel, waving US flags. Police officers escorted the hearse to the church, and stood outside as the bell tolled.
A memorial service was scheduled later for another victim, Lu Lingzi, a 23-year-old graduate student from China.
The third person to die in the attack was an eight-year old boy. One policeman was killed and another injured during the manhunt.
Of those injured in the attack, 13 lost limbs. More than 50 people remained in hospital on Monday, three of them in critical condition.
No motive for the attack has been established. The brothers, who originate from Chechnya in southern Russia, had been living in the US for about a decade.
Boston police have said the brothers were probably planning further attacks.
US lawmakers have questioned why the FBI had failed to spot the danger from Tamerlan Tsarnaev after Russia had asked the US agency to question him two years ago.
The elder of the brothers spent several months in southern Russia last year, mostly in Dagestan but also briefly, it appears, in Chechnya itself.