Boston police officially declared wanted Dzhokhar Tsarnaev suspected of a terrorist attack, RIA Novosti reported.
"The suspect was identified as 19-year-old Dzhohar Tsarnaev from Cambridge. The suspect is armed and dangerous," the police stated in its official blog on Twitter.
Tsarnaev's photo is attached to the statement.
Associated Press agency reported on Friday referring to unnamed sources that the suspects of the Boston attack were from a Russian regions bordering with Chechnya. According to media reports, 19-year-old Dzhokhar Tsarnaev managed to escape from the police, while his brother, Tamerlan, died of the wounds he had received during the arrest.
Two explosions with a12-second interval occured in Boston during the International Marathon on Tuesday night. According to the police, the bombs were installed at a 50-100-meter distance from each other. Three people, including a 8-year child, were killed; more than 140 people were injured.