A US jury sentenced Boston bomber Dzhokhar Tsarnaev to death on Friday for perpetrating one of the bloodiest assaults in America since the September 11, 2001 attacks.

It took the jury more than 14 hours to choose the death sentence on six of the 17 capital counts on which the 21-year-old Muslim former university student of Chechen descent was last month convicted over the April 2013 attacks.