The US-led coalition against the ISIS group is to meet next week in Rome, the State Department said, confirming Secretary of State John Kerry will attend.
"Coalition partners will review progress to date and discuss ways to further intensify commitments across all lines of effort to degrade and defeat this terrorist group," the department said.
Kerry is due in Rome on Tuesday for the conference.
The coalition of mainly Western and Arab powers is training and arming Iraqi government and Syrian rebel forces to fight the ISIS group, while carrying out its own air strikes.
Officials are also considering a possible intervention against the jihadist group in Libya, perhaps led by Italy, the host of next week's conference.
According to the State Department, the members of the coalition to be represented will include Australia, Bahrain, Belgium, Britain, Canada, Denmark, Egypt, the European Union, France, Germany, Iraq, Italy, Jordan, Kuwait, New Zealand, the Netherlands, Norway, Qatar, Saudi Arabia, Spain, Sweden, Turkey and United Arab Emirates.
The United Nations will send observers.
After Tuesday's conference, Kerry will head on to London for a conference of donor countries looking to support aid and reconstruction in Libya, hosted by Britain, Germany, Norway, Kuwait and the United Nations.