Speaking at a news conference with France's Defence Minister Jean-Yves Le Drian, Carter said there was broad agreement on a coordinated plan to battle IS over the next year and take back key cities in Iraq and Syria from the militants.
"We agreed that we all must do more," Carter said shortly after a working lunch with Le Drian and defence ministers from France, Australia, Germany, Italy, the Netherlands and the United Kingdom.
Carter urged the coalition to seize the opportunity now to hasten the Islamic State group's defeat.
The US has mapped out a coordinated campaign against IS over the next year, and Carter laid out the plans to the ministers during the meeting, which was co-hosted by France.
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"Because Daesh is retreating and we have managed to affect its resources in the ground, it is the moment to increase our collective forces with a coherent military strategy," Le Drian said, using the Arabic acronym for the Islamic State.
The defence ministers also discussed plans to retake two major cities in Iraq and Syria that serve as power centers for IS.
The coalition wants to help Iraqi and Kurdish peshmerga forces retake Mosul in northern Iraq and to assist the Syrian moderate forces in ousting Islamic State militants from Raqqa, Syria, the group's self-proclaimed capital.
"Raqqa and Mosul must be won back," Le Drian said, adding that it can only succeed if the coalition supports the local forces on the ground in Iraq and Syria.
While European nations have been heavily involved, the US would like to see more direct military contributions, both equipment and training, from Arab and Asian countries.
Arab nations joined the coalition's airstrike campaign early on, but their participation has waned a bit over time, particularly as the fight between Saudi Arabia and Iran-backed rebels in Yemen has increased.