US delivers arms to Kurdish fighters in Syria
"We have begun to transfer small arms and vehicles to the Kurdish elements" of the Syrian Democratic Forces (SDF), Pentagon spokesman Major Adrian Rankine-Galloway said.
The weapons include AK-47s and small-caliber machine guns, Rankine-Galloway added.
President Donald Trump this month approved arming the fighters from the Kurdish Peoples' Protection Units (YPG) - which is part of the Syrian Democratic Forces - drawing strong condemnation from Turkey, a NATO ally.
Ankara accuses the YPG of being the Syrian wing of the Kurdistan Workers' Party (PKK), which has fought a bloody separatist war with Turkey leading to tens of thousands of deaths.
Turkey's concerns about the YPG were significant enough for Ankara to launch its own military operation inside Syria in August 2016, dubbed Euphrates Shield.
The operation had the dual goals of targeting IS and the Kurdish militia, particularly to prevent the YPG from controlling a contiguous strip of territory along the Syria-Turkey border.
While the Kurds have failed to link up the two "cantons" under their control in the north-east with the Afrin region to the west, the Turkish operation has largely floundered.
The SDF have now advanced to within a few miles of Raqqa on several fronts, and this month captured the strategic town of Tabqa and the adjacent dam from the jihadists.
Washington has sought to placate Ankara by saying the weapons will be handed out judiciously, and that it will monitor these to make sure they don't go into Turkey.
The Pentagon insists the SDF are the only fighting force currently on the ground capable of seizing IS' self-declared capital.