Ryan Crocker said, however, that he told the Iranians that it would be necessary for Iran to alter it's behavior and stop arming, funding and training militants.
"This is about actions not just principles, and I laid out to the Iranians direct, specific concerns about their behavior in Iraq and their support for militias that are fighting Iraqi and coalition forces," Crocker told a Green Zone news conference.
Crocker also disclosed that the Iranians said they would be proposing a second session.
"We will consider that when we receive it," Crocker told reporters in the U.S.-controlled Green Zone.
Iran proposed setting up a "trilateral security mechanism" that would include the U.S., Iraq and Iran, Crocker said, adding that any move on that proposal would need study in Washington.
"The purpose this meeting was not to arrange other meetings," he said.