Dzhokhar Tsarnaev, the teenager accused of carrying out the Boston bombings, on Wednesday pleaded not guilty to all charges in US federal court, nearly three months after the deadly April attacks.
"Not guilty," the 19-year-old Tsarnaev -- in handcuffs, shackles and wearing an orange jumpsuit -- said repeatedly as the 30 counts were read out at the arraignment in Boston, which lasted seven minutes.
Seventeen of those counts are punishable by the death penalty or life imprisonment.
Security was tight at the courthouse for the hearing, which marked the first time Tsarnaev -- an ethnic Chechen Muslim and naturalized US citizen -- had been seen in public since his capture.
The shaggy-haired teen, who was seriously wounded as he tried to evade capture in the days after the attacks, still sported a cast on his left arm.
The courtroom was packed with emotional victims of the April 15 bombings at the Boston Marathon finish line, some of whom needed canes or crutches to walk, and their relatives.
"I just want to know why," said Liz Norden, whose two sons aged 32 and 33 each lost a leg in the attacks.
"I just don't understand how you can live in this country and feel that way."
Also in court were many journalists and a few people who identified themselves as friends or supporters of Tsarnaev, who had been a student at the University of Massachusetts at Dartmouth.
"Exonerate Jahar," read a small sign carried by Karina Figueroa, who traveled from New York for the hearing. Tsarnaev's friends pronounced his name "Jahar."
"He is innocent. I don't see any evidence," Figueroa said.
The attacks, which left three people dead and more than 260 wounded, stunned America with scenes of carnage and chaos at one of the country's premier sporting events.
The pressure cooker devices were packed with metal fragments to cause maximum damage, and several people lost one or more limbs.
Tsarnaev, who had lived in the Boston area for a decade, had seemed well integrated into American life.
He is accused of plotting and carrying out the attacks with his 26-year-old brother Tamerlan, who died in a shootout with police as the pair tried to escape the Boston area several days later.
He is also charged in connection with the shooting death of a campus police officer at the Massachusetts Institute of Technology during the brothers' wild overnight getaway attempt.
The younger Tsarnaev was captured on April 19 after a huge manhunt that virtually shut down the Boston area. Police found him hiding in a boat in a suburban backyard.
He allegedly scrawled a rambling explanation of his motives for the Boston attacks on an interior wall of the boat.
"The US government is killing our innocent civilians," Tsarnaev wrote.
"I can't stand to see such evil go unpunished ... we Muslims are one body, you hurt one you hurt us all.
"Now I don't like killing innocent people it is forbidden in Islam but ... stop killing our innocent people and we will stop."
The charges against Tsarnaev include using a weapon of mass destruction resulting in death, as well as conspiracy and bombing of a place of public use resulting in death, and carjacking.
The brothers are said to have built the bombs with help from an online Al-Qaeda magazine, but are not believed to have received help from any organized group, according to the indictment.
They were also said to have watched sermons by Yemeni-born American radical Islamic cleric Anwar al-Awlaqi, a key figure in Al-Qaeda in the Arabian Peninsula who was killed in a drone strike in Yemen in 2011.
The two bombs were detonated seconds apart, killing a boy, a Chinese student and a woman restaurant manager. At least 13 of the injured had limbs torn off.
The trial is not expected to begin any time soon, but would last three to four months, Judge Marianne Bowler said Wednesday.
The decision on whether to seek the death penalty is up to US Attorney General Eric Holder.
The next hearing was set for September 23. Tsarnaev is not expected to appear.