Lawyers for Boston marathon bombing suspect Dzhokhar Tsarnaev asked a judge Wednesday to lift restrictions placed on him in prison, arguing that the conditions are overly harsh, have left him nearly totally isolated and are impairing their ability to defend him.

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. …

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. …

Tsarnaev’s lawyers say prosecutors have presented no evidence that the special restrictions are needed in Tsarnaev’s case.