Bangladesh's elite security force Thursday arrested the head of a banned hardline Islamist group over the murder of two atheist bloggers that sparked international outrage, a spokesman said.

The Rapid Action Battalion spokesman said Mohammad Abul Bashar, who heads the outlawed Ansarullah Bangla Team, and two others were arrested in the capital Dhaka.

"They are suspects in the murders of bloggers Avijit Roy and Ananta Bijoy Das," Mufti Mahmud Khan told AFP, referring to the writers who were hacked to death earlier this year.