Rice: White House already looking ahead to prevent ‘next attack’

"I think your gravest worry at this point, because in many ways, this day in Boston is your worst nightmare – an attack on American soil. But you really have to get over that fear and move on to making certain that you’ll prevent the next attack, if there is to be one,” said Rice. “Perhaps this was the act of a single individual and there’s nothing else coming, but they will wonder whether or not the ricin incident is somehow related."

Capitol Police said Tuesday that a letter addressed to Sen. Roger Wicker (R-Miss.) had tested positive for ricin, a deadly poison.

The news came a day after two bombs went off at the finish line of the Boston Marathon, killing 3 and wounding dozens, but officials have not linked the two events.

Rice, a CBS News contributor said there was a “much better apparatus” in place for dealing with terror threats since the Sept. 11, 2001, attacks.

Rice also called it "odd" that no one has yet stepped forward to claim credit for the explosion that left three people dead and more than 100 wounded on Monday. 

"I do think that’s odd, because normally these jihadist groups, the biggest ones like al Qaeda, would take some kind of responsibility. But because al Qaeda and the jihadists have become so atomized, that doesn’t mean that this isn’t somehow related to the jihadists," Rice said. 

On Tuesday, Obama called the bombing "a heinous and cowardly act" during a public statement in the White House press room. He also reiterated comments from federal, state and local authorities, saying the government does not know the motive behind the attack, or whether it was conducted by a foreign or domestic group or individual.  

Rice said the president has to be "very careful" not to give out premature information to the public. 

"I’m not surprised that very little has been said yet … and it’s entirely possible too that they want to be certain that they’re not tipping off those who might have been responsible," Rice said.