In two weeks, Carter will meet with a broad group of defense ministers where he said he will press those who are in the fight "on paper" but are not doing enough.
"We're prepared to do a great deal because we have the finest fighting force the world has ever seen. We can do a lot ourselves," Carter said. "The United States does not ask people for favors, but we don't grant favors either, and so we're looking for other people to play their part."
To get those players on board, Carter said he would share U.S. operations plans with defense ministers.
Carter said the United States would continue to keep boots on the ground, but would remain focused on advising and assisting Iraqi, Kurdish and Syrian Arab forces to take and hold territory.
"I don't think we or anybody else can substitute for them, but there's a lot we can do to enable them, including being on the ground with them," he said.
"We're looking for opportunities to do more, and there will be boots on the ground — I want to be clear about that — but it's a strategic question, whether you are enabling local forces to take and hold, rather than trying to substitute for them."