Britain's top military official says countries allied against the Islamic State group have to capitalize on recent gains made against the extremist organization.

Michael Fallon said Wednesday in Paris that the Islamic State group is being hit "in its own heartland" and that Britain carries out airstrikes six days a week, primarily in Iraq.

He spoke ahead of a meeting with U.S. Defense Secretary Ash Carter and counterparts from France, Germany, Australia, the Netherlands and Italy.

The group is mapping out plans for the coming year's fight against the Islamic State group. No Arab country was invited to the meeting, but Carter on Tuesday said he hoped countries from the region would increase their contribution.