"Pakistan is a continuing problem for Afghanistan and a continuing problem for us. It's really that frontier between the two countries that is the most dangerous threat to not just Afghanistan but I think also to Pakistan," Rice told CNN.
"There's a lot of work yet to do in Afghanistan, but I think we can in a reasonable amount of time train Afghan security forces that are capable of preventing an existential threat to the Afghan government, help the Afghans to create more decent governance, particularly perhaps in the provinces," the former Secretary of State said.
Rice, whose memoir 'No Higher Honor' was released this week, said "the real wild card is whether or not Pakistan is really going to go after the extremists in that northwest frontier. That's really where the issue is."
She said it is quite obvious that Afghan President Hamid Karzai is not a perfect partner "but he isn't Taliban, either, and he's not harbouring al-Qaeda in his country.
"This is a country that no longer has an al-Qaeda safe haven. It is a country that actually has made some progress toward decent governance."