Kerry says he delivered that message to Egyptian President Abdel-Fattah el-Sissi during their meeting Sunday in Cairo.
Kerry says he plans to make the same case to other leaders in Sunni-dominated Arab states over the next several days.
Kerry says the region's security is facing a critical moment as the Islamic State of Iraq and the Levant gains ground in Iraq.
The group has taken over parts of Syria in what is rapidly deteriorating into a cross-border war.
He'll urge Arab states to work together to defeat the group.
Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.