The United States on Tuesday began providing small arms to Kurdish fighters battling the Islamic State group in northern Syria, the Pentagon said, fulfilling a pledge that has infuriated Turkey.
The weapons transfers have begun ahead of an upcoming offensive to recapture Raqa, the last major bastion for IS 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, referring to a Kurdish-Syrian Arab alliance fighting IS.
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), drawing strong condemnation from Turkey.
Ankara says the YPG is linked to Kurdistan Workers' Party (PKK) separatists, who have waged an insurgency since 1984 that has killed more than 40,000 people inside Turkey.
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 northeast with the Afrin region to the west, the Turkish operation has largely floundered.
The SDF have now advanced to within a few miles of Raqa 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 Raqa.
Still, Washington must strike a careful balance. Turkey is a NATO ally and home to a key airbase that the US-led coalition uses to hit IS.