The Left party also claimed all terrorist outfits are "directly or indirectly" products of phobia created by the US.
"The growing fundamentalism of all kinds throughout the world is no doubt a result of the wrong policies of the governments which put one section against the other.
"It should also be remembered that all terrorist outfits are directly or indirectly products of terror phobia created by the US," the party said in a statement.
20 foreigners, including an Indian student, were brutally murdered by militants inside Holey Artisan Bakery in Dhaka's diplomatic zone, all possibly slaughtered on late Friday.
In the rescue operation, security personnel in that country killed six attackers, while one was captured alive on July 2, ending Bangladesh's worst terror attack.