Boston bomber Dzhokhar Tsarnaev cries during trial as aunt weeps uncontrollably on the stand

The 21-year was visibly emotional for the first time since being convicted of the Boston Marathon attack

An emotional relative of Dzhokhar Tsarnaev leaves federal court in Boston after testifying Monday, May 4, 2015, during the penalty phase in Tsarnaev's trial. (AP)

Boston bomber Dzhokhar Tsarnaev showed a rare display of emotion on Monday and cried as his aunt gave evidence in his trial.

Tsarnaev, 21, was seen wiping tears away with a tissue as his aunt Patimat Suleimanova wept uncontrollably after taking the stand on Monday, according to the Associated Press.

The Chechen-American’s tears contrasted heavily with images released in April showing him swearing at a prison surveillance camera.

Five of Tsarnaev’s relatives were called to testify in the penalty stage of his trial for the bombing of the Boston Marathon, which killed three people and wounded over 260 others.

Boston Marathon bomber Dzhokhar Tsarnaev (AP Photo/Federal Bureau of Investigation, File)

But Ms Suleimanova became so upset that Judge George O'Toole Jr at one point suggested another witness be called to the stand so she could compose herself. She was only able to answer questions about her name, age and place of birth.

Tsarnaev also blew a kiss at his other aunt, who cried during her testimony, as he was led away during a break in the hearing.

His cousin Raisat Suleimanova testified that he was a kind and gentle child who once cried while watching The Lion King.

"I think that his kindness made everybody around him kind," Ms Suleimanova added, prompting prosecutor Bill Weinreb to ask: “The bombing of innocent people is not an act of kindness, is it?”

Prosecutors had asked for Tsarnaev’s family to give evidence as soon as possible, as they arrived in Boston on 23 April and are being protected by a team of FBI agents.

Rosa Booth, a high school friend, remembered him as “goofy” and with “a sweetness about him, maybe a little shy”. She said he did not talk to her about politics or religion.

Prosecutors seeking the death penalty for Tsarnaev’s role in the 2013 bombings claim he undertook an equal role to his brother Tamerlan, who was killed by police.

His legal team claims Tsarnaev was under the influence of his older brother, who they say masterminded the attack.