"We recognize that we're in a good-to-better place in terms of security," Petraeus told CNN. "But we recognize that progress is tenuous and it is reversible and there are challenges."

Speaking to CNN on the fifth anniversary of the Iraq war's start, Petraeus said he would like to continue to draw down troops but would do so only if the action wouldn't jeopardize the gains made, especially since the surge in troops last year.

More Iraqis are realizing "extremist ideology wasn't something they could subscribe to" and have become more accepting of the changes.

But with at least 130 deaths and 200-plus injuries reported since Monday, Petraeus recognized the streets were still dangerous.

"Clearly there have been in recent weeks headline-grabbing attacks," he said to CNN. "Al-Qaida is intent in reigniting sectarian violence."

"Iraq still a work in progress."