Tsarnaev's lawyers said in court documents that he has been confined to his cell except for visits from them and "very limited access" to a small outdoor enclosure.
Tsarnaev, 20, is accused of building and planting bombs near the finish line of the April 15 marathon, killing three people and injuring more than 260. Authorities say he and his older brother, Tamerlan Tsarnaev, 26, ethnic Chechens from Russia who emigrated to the United States as children, planned and carried out the attack to retaliate against the United States for its involvement in Muslim countries.
Authorities said he had scrawled anti-American messages on the inside of the boat, including "The US Government is killing our innocent civilians" and "We Muslims are one body, you hurt one you hurt us all."
In their motion, Tsarnaev's lawyers said "Special Administrative Measures" were imposed on their client beginning in August, at the request of US Attorney Carmen Ortiz and the approval of US Attorney General Eric Holder.
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"SAMs," as they are known, are used in terrorism cases and other high-profile cases when authorities allege there is "substantial risk" that a defendant's communications or contacts with people "could result in death or serious bodily injury" to others. The special restrictions were placed on shoe bomb suspect Richard Reid, "American Taliban" John Walker Lindh and other terror suspects.
"The government has not alleged that Mr Tsarnaev has done or said anything since his arrest to commit violence, incite violence, or engage in communications that pose a security threat," his lawyers argued in the filing.
They also said the special measures limit Tsarnaev's interaction with people who are helping the defense and restrict the communications and other activities of the defense team.
A spokeswoman for Ortiz did not immediately return a call seeking comment.