Kerry also said that US air strikes, including from unmanned drones, "may well" be an option that President Barack Obama chooses to try to halt the advance of fighters from the al-Qaida-inspired Islamic State of Iraq and the Levant, or ISIL.
In the last week, ISIL has taken Iraq's second-largest city, Mosul, and Saddam Hussein's hometown of Tikrit in a lightening offensive that has plunged Iraq into its worst crisis since the 2011 withdrawal of US troops. Over the weekend, militants posted graphic photos that appeared to show their gunmen massacring scores of captured Iraqi soldiers.
"We're open to discussions if there is something constructive that can be contributed by Iran, if Iran is prepared to do something that is going to respect the integrity and sovereignty of Iraq and ability of the government to reform," Kerry said.
"At this moment, I think we need to go step-by-step and see what in fact might be a reality. But I would not rule out anything that would be constructive in providing real stability, a respect for the constitution, a respect for the election process and a respect for the ability of the Iraqi people to form a government that represents all the interests of Iraq," he said. "We are open to any constructive process here that would minimize the violence."
In addition to possible discussions with Iran, Kerry said that Obama administration is actively considering unilateral airstrikes to slow the ISIL insurgency that is threatening the government of President Nouri al-Maliki.