SYDNEY — The Obama administration has begun directly providing weapons to Kurdish forces who have started to make gains against Islamic militants in northern Iraq, senior U.S. officials said Monday.

Previously, the U.S. had insisted on only selling arms to the Iraqi government in Baghdad, but the Kurdish peshmerga fighters had been losing ground to Islamic State militants in recent weeks.

The officials wouldn’t say which U.S. agency is providing the arms or what weapons are being sent, but one official said it isn’t the Pentagon. The CIA has historically done similar quiet arming operations.

The move to directly aid the Kurds underscores the level of U.S. concern about the Islamic State militants’ gains in the north, and reflects the persistent administration view that the Iraqis must take the necessary steps to solve their own security problems.

To bolster that effort, the administration is also very close to approving plans for the Pentagon to arm the Kurds, a senior official said. In recent days, the U.S. military has been helping facilitate weapons deliveries from the Iraqis to the Kurds, providing logistic assistance and transportation to the north.