A federal court spokesman said Tsarnaev, 19, made his first court appearance on the charges stemming from last week's finish line bombing from his hospital bed at Beth Israel Deaconess Medical Center.
The bombing killed three people and injured more than 170. Tsarnaev was injured Friday during a shootout with police that left his brother, Tamerlan, 26, dead in the early morning hours and again as police closed in on him later in the day.
"Although our investigation is ongoing, today's charges bring a successful end to a tragic week for the city of Boston and for our country," U.S. Attorney General Eric Holder said. "We've once again shown that those who target innocent Americans and attempt to terrorize our cities will not escape from justice. We will hold those who are responsible for these heinous acts accountable to the fullest extent of the law."
Prosecutors said in addition to the conspiracy charge, Tsarnaev also is accused of malicious destruction of property by means of an explosive device resulting in death, the Boston Globe reported.
An FBI affidavit said review of surveillance tapes, pictures and videos taken by the public indicates the suspect stood next to one of the bombs for four minutes with a cellphone in hand, apparently taking a picture of the device before walking away.
"Approximately 30 seconds before the first explosion, he lifts his phone to his ear as if he is speaking on his cell phone, and keeps it there for approximately 18 seconds. A few seconds after he finishes the call, the large crowd of people around him can be seen reacting to the first explosion," the document said.
"Virtually every head turns to the east [towards the finish line] and stares in that direction in apparent bewilderment and alarm. Bomber Two, virtually alone among the individuals in front of the restaurant, appears calm. He glances to the east and then calmly but rapidly begins moving west, away from the direction of the finish line.
"He walks away without his knapsack, having left it on the ground where he had been standing. Approximately, 10 seconds later, an explosion occurs in the location where Bomber Two had placed his knapsack."
A second affidavit reveals "a large pyrotechnic, a black jacket and white hat of the same general appearance as those worn by Bomber Two at the Boston Marathon" were found in Tsarnaev's University of Massachusetts-Dartmouth dorm room, the Globe said.
The charges came as Krystle Campbell, 29, one of the three killed in last Monday's bombing, was buried. A moment of silence was to be observed at 2:50 p.m., the time the first bomb exploded.
The day's event will also include a memorial service at Boston University and a funeral.
A memorial service is scheduled for Wednesday for Sean A. Collier, the Massachusetts Institute of Technology police officer killed Thursday night in his patrol car allegedly by the brothers,
Boston Police Commissioner Ed Davis told CNN Monday evidence collected so far indicates the brothers were planning more mayhem.
"The two suspects were armed with handguns at the scene of the shoot-out. And there were multiple explosive devices, including a large one that was similar to the pressure cooker device that was found on Boylston Street [at the finish line]," Davis said.
"I saw that with my own eyes. I believe that the only reason that someone would have those in their possession was to further attack people and cause more -- more death and destruction."
A wake for Krystle Campbell, 29, began the week of memorials. Campbell died from wounds she received in the bombing. She was buried Monday.
Cardinal Sean P. O'Malley, speaking at the Cathedral of the Holy Cross in Boston, noted many of the 170 wounded at the race had prayed at the church the week before.
O'Malley called on those in attendance to "be a people of reconciliation, not revenge."
About three dozen victims remained hospitalized Monday, with three in critical condition.
Tsarnaev was in critical but stable condition with a gunshot wound to the neck, Boston police said, but was responding to questions in writing.
The type of neck wound indicates he may have tried to kill himself, authorities said.
It "had the appearance of a close-range, self-inflicted style," a senior U.S. official told The New York Times.
Investigators are asking him about other possible cell members and other unexploded bombs, sources told ABC. The sources didn't say what Tsarnaev wrote in response.
Boston Mayor Thomas Menino and Davis said they believed Tsarnaev and his brother acted alone.
When the suspects seized a Mercedes-Benz sport utility vehicle and held the driver hostage, they told him they planned to go to New York, the senior U.S. official told the Times.
It was not immediately clear if they told the driver what they planned to do in New York.
Davis also told The Boston Globe Tamerlan Tsarnaev appeared to have died because his younger brother drove over him in the stolen SUV in a desperate getaway.
He said the older Tsarnaev was alive and struggling with police until Dzhokhar Tsarnaev drove over him, dragging him on the pavement and apparently inflicting the fatal injuries that killed him.
The younger Tsarnaev was captured Friday night, after hiding for hours in a boat stored in a Watertown back yard.
The Globe reported Tamerlan Tsarnaev angrily disrupted talks at his mosque that he though conflicted with Islamic teachings. One of those talks involved a comparison between the Prophet Muhammad and civil rights leader the Rev. Martin Luther King Jr. In the second incident, Tsarnaev called the speaker a hypocrite and accused him of contaminating people's minds.