Zulfikar Ali says the two men, both police officers, were charged with failing to provide Bhutto with proper security and with destroying evidence.
Five other suspects already on trial in the case are members of the Pakistani Taliban. They will be given a new trial so they can be tried together with the new defendants.
The prosecutor says a judge read out the charges against all seven at a closed-door hearing Saturday in the garrison city of Rawalpindi, where Bhutto was killed.
Bhutto was killed Dec. 27, 2007, in a gun and suicide-bomb attack at a rally just weeks after returning home from years in self-imposed exile.