The White House has approved the deployment of small teams of U.S. Special Forces to locations in northeastern Syria, expanding America’s direct role on the ground in support of U.S.-backed Syrian rebel forces as they prepare for a new military campaign against Islamic State militants in their stronghold in Raqqa, officials said.

The new deployment would amount to the first sustained U.S. ground presence in Syria. White House press secretary Josh Earnest said the U.S. role in Syria would, nonetheless, remain narrow—specifically to “build the capacity of local forces so that they can be more effective.”

Mr. Earnest, facing a series of questions about how the decision comports with President Barack Obama’s promise not to put U.S. boots on the ground in Syria, said the president’s commitment was to not ordering a large-scale deployment of ground troops. […]