Boston Police and Massachusetts State Police stand guard outside of Beth Israel Deaconess Medical Center, where Dzhokhar Tsarnaev is currently being held. (AFP)
But details of the charges were sealed, a US court official said on Monday.
"There has been a sealed complaint filed," said Gary Wente, circuit executive for the US courts for the first circuit, who said a magistrate judge was present when Tsarnaev was charged at his bed in Beth Israel Deaconess Hospital in Boston.
Tsarnaev was listed in serious condition.
Tsarnaev (19) an ethnic Chechen college student suspected of carrying out the attacks with his older brother, was unable to speak after he was captured with throat injuries sustained during shootouts with police.
Police declined to comment on media reports he was communicating with authorities in writing.
"There have been widely published reports that he is [communicating silently]. I wouldn't dispute that, but I don't have any specific information on that myself," Boston police commissioner Ed Davis told CNN.
"We're very anxious to talk to him and the investigators will be doing that as soon as possible." Police captured Tsarnaev on Friday night to cap a violent week of blasts, shootouts, lockdowns and one of the largest manhunts in US history.
Memorial service
His older brother, Tamerlan Tsarnaev (26) died after a gunfight with police early Friday morning.
The city of Boston crawled back to normal on Monday, a week after twin bombs exploded at the crowded finish line of the city's famous marathon road race, killing three people and wounding 176. Ten of the injured lost limbs.
The crime scene around the blasts was still closed but was expected to reopen within a day or two. Signs declaring "Boston Strong" hung about the city.
Memorial services were set on Monday for two of those killed in the bombings: Krystle Campbell, a 29-year-old restaurant manager, and Chinese graduate student Lingzi Lu. An 8-year-old boy, Martin Richard, was also killed.
Pause at time of bombings
The city also planned to pause at 2.50pm to mark the moment a week ago when the two bombs made of pressure cookers and packed with nails and ball bearings tore through the crowd watching runners complete the Boston Marathon.
In the days that followed, investigators examining thousands of images from surveillance video, media coverage and spectators taking pictures were able to pick out two men as suspects, later identified as the Tsarnaev brothers.
On Tuesday, the day after the attack, the younger Tsarnaev was working out in the gym at the University of Massachusetts-Dartmouth, listening to music on his iPod, when he struck up a conversation with fellow sophomore Zach Bettencourt.
Bettencourt said he and Tsarnaev chatted about the bombings.
"It's crazy this is happening now," Bettencourt recalled Tsarnaev telling him. "This [these bombings] is so easy to do. These tragedies happen all the time in Afghanistan and Iraq."
Police said the Tsarnaev brothers made enough additional bombs for them to believe that more attacks were planned. They were also armed with handguns.
Charges
A shootout with police in the Boston suburb of Watertown early Friday morning left more than 200 spent shell casings in the street.
Neither Tsarnaev brother was licensed to own guns in the towns where they lived, Cambridge, Massachusetts, authorities said on Sunday.
Dzhokhar Tsarnaev could be charged with several crimes including use of weapons of mass destruction, terrorism and bombing of places of public use in addition to homicide, said former federal prosecutor and University of Notre Dame law professor Jimmy Gurulé.
Because death resulted, each statute authorises the death penalty, he said.
Though the case is likely to involve officials at the highest levels including attorney general Eric Holder, the prosecutor in charge will be Carmen Ortiz, the US attorney for the district of Massachusetts.
Ortiz has faced criticism for coming down too hard on some defendants, but that approach may become a legal asset for the biggest case of her career, said attorneys who have faced off against her.
'Framed'
The Tsarnaev brothers emigrated to the US a decade ago from Dagestan, a predominantly Muslim region in Russia's Caucasus.
The men's parents, who moved back to southern Russia some time ago, have said their sons were framed.
Much of investigators' attention has focused on a trip to Russia last year by Tamerlan Tsarnaev, and whether he became involved with or was influenced by Chechen separatists or Islamist extremists there.
Tamerlan Tsarnaev traveled to Moscow in January 2012 and spent six months in Dagestan, a law enforcement source said.
Neighbors in Makhachkala, the region's capital city, said he kept a low profile while visiting there last summer, helping his father renovate an apartment unit.
That trip, combined with Russian interest in Tamerlan communicated to US authorities and an FBI interview of him in 2011, have raised questions whether danger signals were missed. – Reuters