The US secretary of state said Iran had a role to play in destroying militant group Islamic State (ISIL).
But Iran’s Supreme Leader Ayatollah Khamenei said he had rejected Washington’s offer for talks on fighting the group.
Iran is the main ally of ISIL’s main foes in both Iraq and Syria.
“The fact is there is a role for nearly every country in the world to play, including Iran whose foreign minister is here with us today. ISIL poses a threat to all of us and we’re committed to working in close partnership with a new Iraqi government and countries around the world to defeat it,” said Kerry at a UN Security Council meeting.
French fighter jets have carried out airstrikes in Iraq against ISIL.
France is the first foreign country to add military muscle to United States airstrikes against ISIL.
French Foreign Minister Laurent Fabius said more operations would follow.
“In the coming days, without engaging troops on the ground we will continue coordinating our efforts with all of those, who wish to commit working with the Iraqi forces and Kurdish fighters,” he said.
Meanwhile US President Barack Obama has signed into law a bill authorising the military to arm and train Syrian rebels fighting ISIL.
He said America is leading the coalition that will degrade and ultimately destroy the terrorist group.