The United States has begun sending small arms to Kurdish fighters battling the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group in northern Syria, despite concerns from NATO-ally Turkey.

The Pentagon said on Tuesday that the weapons shipments began ahead of an upcoming offensive to recapture Raqqa, the de facto capital of ISIL in northern 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 sent to the SDF's Kurdish Peoples' Protection Units (YPG) include AK-47s and small-calibre machine guns, Rankine-Galloway added.

US President Donald Trump earlier this month approved arming the YPG fighters, angering Turkey.

The Pentagon said then that the YPG are "the only force on the ground that can successfully seize Raqqa in the near future".



There was no immediate reaction from Turkey regarding the start of the weapons transfer.

Turkish officials have previously warned the US that its decision to arm Kurdish forces fighting ISIL in Syria could end up hurting Washington.

Ankara says YPG fighters are linked to Kurdistan Workers' Party (PKK) separatists inside Turkey, who have waged an armed campaign since 1984 that has killed more than 40,000 people.

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Turkey considers the Kurdish forces to be "terrorists" and fears any weapons sent to the YPG could end up in the hands of the PKK. In August 2016, Ankara launched its own military operation inside Syria, targeting ISIL and Kurdish groups, called Euphrates Shield.



Speaking to Al Jazeera last month, Erdogan criticised Trump's predecessor, Barack Obama, over an agreement between the two to fight what he described as "terrorist groups" operating in Turkey.



"With President Obama, we had a mutual agreement about the PKK - but Obama deceived us. I don't believe the Trump administration will do the same," Erdogan said.



"The YPG is an arm of the PKK. We must put an end to this," he added.



"We can't destroy one terrorist group with another one. We are strategic partners with the US."

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 do not go into Turkey.

Raqqa offensive

The SDF has been encircling Raqqa since November.

The US-backed group has now advanced to within a few miles of the ISIL stronghold on several fronts, and this month captured the strategic town of Tabqa and the adjacent dam.

Following the capture of Tabqa, the SDF said it will soon begin a final attack to capture Raqqa. At the time, a SDF commander said forces would begin "entering and storming the city ... at the start of the summer".

On Monday, the UK-based Syrian Observatory for Human Rights said at least 13 people have been killed in suspected US-led coalition air strikes on Raqqa and suspected rocket attacks fired by the Kurdish Ghadab al-Furat group.

Separately, Syrian rebels said this week the US and its allies are sending more arms to try to fend off a new push into the southeast by what they call Iran-backed militias aiming to open an overland supply route between Iraq and Syria.