An international coalition is pushing back Islamic State militants in their Syrian and Iraqi strongholds, but the group is threatening Libya and could seize the nation's oil wealth, U.S. Secretary of State John Kerry said on Tuesday.

Officials from 23 countries met in Rome to review the fight against Islamic State militants, who have created a self-proclaimed caliphate across swaths of Syria and Iraq, and are spreading into other countries, notably Libya.

While Western officials worry about the growing threat posed by Islamic State in the former Italian colony, there was no suggestion that foreign powers were preparing to launch a major military offensive against them there for now.