Federal prosecutors charged the surviving man suspected of bombing the finish of last week's Boston marathon with one count of using a weapon of mass destruction and one count of malicious destruction of property resulting in death, the Justice Department said today.
The charges authorise penalties including death, life in prison or a term in prison for any number of years, the department said in a statement.
Dzhokhar Tsarnaev, who was seriously injured in a firefight with police before his Friday arrest, was charged in his hospital bed earlier today.
The ethnic Chechen college student suspected with his deceased older brother in the Boston Marathon bombing remained hospitalised under armed guard, severely wounded and unable to speak.
Tsarnaev (19), was captured with throat injuries that, coupled with sedatives administered at the Boston hospital where he is being treated, had left him incapable of speech and initially prevented authorities from questioning him.
Late yesterday, media reported he was awake and responding in writing to questions at Boston's Beth Israel Deaconess Medical Center.
But Boston Police Commissioner Ed Davis told CNN he could not confirm that. "We're very anxious to talk to him and the investigators will be doing that as soon as possible," Mr Davis said. Tsarnaev's capture on Friday night ended a manhunt that virtually shut down greater Boston for some 20 hours.
His older brother, Tamerlan Tsarnaev (26), was pronounced dead after a gunfight with police a day earlier. Investigators are seeking, among things, to determine whether the two suspects acted alone.
Boston's police commissioner and mayor have both said they believed the brothers were on their own.
"I am confident that they were the two major actors in the violence that occurred," Mr Davis told CNN yesterday.
Mr Davis also said investigators have discovered at least four undetonated devices, one of them similar to the two pressure cooker bombs set off at the Boston Marathon, and that he believed the suspects were planning additional attacks.
Still, 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.
The brothers emigrated to the United States a decade ago from Dagestan, a predominantly Muslim region in Russia's Caucasus. They are accused of planting and setting off two homemade bombs near the crowded finish line of the Boston Marathon last Monday, killing three people and injuring more than 170 others.
US Attorney Carmen Ortiz, the federal prosecutor for the Boston area, was preparing criminal charges against the younger Tsarnaev, a naturalised US citizen, according to Mr Davis.
It was not clear when charges would be filed, but it could as early as today.
Tamerlan Tsarnaev traveled to Moscow in January 2012 and spent six months in Dagestan, a law enforcement source said.
Neighbours 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.
A group leading an Islamist insurgency against Russia said yesterday it was not at war with the United States, distancing itself from the Boston bombings. The insurgency is rooted in two separatist wars that Russian troops waged against Chechen separatists following the fall of the Soviet Union.
Photos and video footage of the Tsarnaev brothers, allegedly in the act of planting bombs at the marathon, were first circulated by the FBI on Thursday with an appeal for help in locating the then-unidentified pair.
Police say the suspects shot dead a campus police officer at the Massachusetts Institute of Technology in Cambridge later that night, then hijacked a sport utility vehicle before opening fire and hurling explosives at pursuing law enforcement.
During this confrontation, according to police, a transit police officer was badly injured and the older Tsarnaev, walking toward officers and firing until he ran out of ammunition, was tackled by police, only to be struck by the SUV as his brother sped away in the vehicle.
The younger Tsarnaev later abandoned the vehicle and vanished, leading authorities to impose a lockdown on the city of Boston and surrounding communities before he was found and arrested in the suburb of Watertown the following night.
He turned up spattered with blood and hiding inside a covered boat parked in a back yard. Students returning to campus yesterday at the University of Massachusetts-Dartmouth, where Dzhokhar Tsarnaev was enrolled, recalled seeing him back in the dorm, at class and even working out in the gym a day or two after the bombings before realising he was suspected in the crime.
The brothers spent their early years in a small community of Chechens in the central Asian country of Kyrgyzstan, a mainly Muslim nation of 5.5 million. They moved in 2001 to Dagestan. The men's parents, who moved back to southern Russia some time ago, have said their sons were framed.
US attorney Carmen Ortiz, the federal prosecutor for the Boston area, was preparing criminal charges, according to Boston Police Commissioner Ed Davis. It was not clear when charges would be filed.
Whether prosecutors ultimately decide to seek the death penalty if Tsarnaev were convicted hinges on various factors, such as his age, his apparent lack of a prior criminal history and whether he might have information leading to other suspects, legal experts say.
Students returning to campus today at the University of Massachusetts-Dartmouth, where Dzhokhar Tsarnaev was enrolled, recalled seeing him back in the dorm, at class and even working out in the gym a day or two after the bombings before realising he was suspected in the crime.
Boston's police commissioner said investigators discovered at least four unexploded devices, including one similar to the two pressure cooker bombs detonated at the Boston Marathon.
"I personally believe they were (planning other attacks)," he said yesterday on CBS television's Face the Nation.
Later on CNN, Mr Davis said he was "confident" the two brothers "were the two major actors in the violence that occurred."
The men's parents, who moved back to southern Russia, have said their sons were framed.
In the neighbouring city of Cambridge, police stationed themselves across from a home where various members of the Tsarnaev family had lived, advising bystanders to move on.
Patricia McMillan, who lives two doors down, said she last saw Tamerlan Tsarnaev in the neighborhood the Wednesday before the bombing, noting he had shaved off his beard and that he was smoking.
Tamerlan Tsarnaev traveled to Moscow in January 2012 and spent six months in the region, a law enforcement source said.
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.
It was unclear if he could have had contact with militant Islamist groups in southern Russia's restive Caucasus region.
A group leading an Islamist insurgency against Russia said yesterday it was not at war with the United States, distancing itself from the Boston bombings.
"We are fighting with Russia, which is responsible not only for the occupation of the Caucasus but for monstrous crimes against Muslims," said a statement from Caucasus Emirate militants operating in Dagestan.
The insurgency is rooted in two separatist wars that Russian troops waged against Chechen separatists following the fall of the Soviet Union.
The brothers spent their early years in a small community of Chechens in the central Asian country of Kyrgyzstan, a mainly Muslim nation of 5.5 million. They moved in 2001 to Dagestan, a southern Russian province where their parents now live.
Neighbours said they noticed nothing unusual about Tamerlan Tsarnaev, who this summer helped his father renovate his first floor apartment in Makhachkala, a bustling city in Dagestan.
"They say he was a fanatic. I didn't see that," said Madina Abdulayeva (45), who runs a small grocery shop across the pot-holed street where he used to come to chat. "We're all Muslim here. We're all part of Islam. We all pray.
Reuters