Acted alone at behest of brother, says Boston blast suspect

CNN reported that Dzhokhar has told investigators that no international terrorist groups were behind them

Dzhokhar Tsarnaev, the alleged Boston blast suspect, has told US investigators that he acted on behalf of his elder brother Tamerlan and no foreign terror group was behind them, according to a media report.

Quoting unnamed official sources, having access to the ongoing interrogation of Dzhokhar, CNN said preliminary interviews with him indicated the two brothers fit the classification of self-radicalised jihadists.

Dzhokhar, 19, is currently being treated for injuries in a city hospital, where he was produced before a District Magistrate.

He is charged with conspiracy to use weapons of mass destruction. He faces death penalty if convicted.

In his preliminary interrogation, through written statements, as he can't speak now, Dzhokhar is believed to have said that his brother - who was killed last week - wanted to defend Islam from attack.

"The government source cautioned that the interviews were preliminary, and that Tsarnaev's account needs to be checked out and followed up on by investigators," CNN reported.

Based on the information it obtained from official sources, CNN claimed that Dzhokhar has told investigators that no international terrorist groups were behind them.

According to the news channel, the two brothers were probably motivated by religious extremism, but they had no direct links with Islamic terrorist groups.

In a similar report, CBS news said Dzhokhar is cooperating with authorities and investigating officials have not found any evidence of ties to terror groups.