Boston bombing suspect Tsarnaev 'wanted to punish America'

His lawyers admit he carried out the attacks but say he was under the influence of his radicalised brother.

If found guilty, the 21-year-old, who is charged with 30 counts, will face life imprisonment or execution.

The jury is to begin their deliberations on Tuesday, after both sides finished their closing arguments.

Three people, including an eight-year-old boy, died after two pressure cooker bombs packed with nails, ball bearings and other shrapnel detonated in April 2013. 

More than 260 people were injured, with many losing limbs. A police officer was shot dead during the massive manhunt.

Assistant US Attorney Aloke Chakravarty said that Mr Tsarnaev targeted the marathon in 2013, because it was a day when the world's attention would be focused on Boston.

"He wanted to terrorise this country," the prosecutor said as closing arguments began at the trial in Boston.

"The defendant thought that his values were more important than the people around him. He wanted to awake the mujahedeen, the holy warriors," he said.

"He wanted to terrorise this country. He wanted to punish America for what it was doing to his people."

Mr Tsarnaev shook his head slightly when Mr Chakravarty referred to him as a terrorist.

As expected, defence attorneys underscored their argument that Mr Tsarnaev was acting under the influence of his elder brother, Tamerlan, who orchestrated the plot.

"Tamerlan built the bombs, Tamerlan murdered officer Collier, Tamerlan led and Dzhokhar followed," lead defence lawyer Judy Clarke said.

"We don't deny that Dzhokhar fully participated in the events, but if not for Tamerlan, it would not have happened," Ms Clarke also said.

She repeatedly referred to him as a "teenager" and as a "kid".

he court was filled with people who have been affected by the bombings and the subsequent manhunt, with several people displaying visible signs of their victimhood - prosthetics, wheelchairs, and hearing aids have all been seen in the courtroom.

Defence lawyers have maintained that his 26-year-old brother, Tamerlan, who died during a massive manhunt, had orchestrated the attacks and by doing so they hope to spare their client the death penalty.

If convicted, a second phase will determine the punishment, and the jury will have to decide whether he will be put to death.

The attacks were the deadliest terror attack on US soil since 9/11.