Washington will "adjust" its delivery of weapons to an anti-jihadist alliance in Syria dominated by Kurdish fighters, Kurdish officials said Monday, insisting that collaboration with the United States will "continue".

The Pentagon, however, was vague about what an adjustment might mean, and the comments come after Turkey said it had received White House assurances that it would halt weapons supplies to the Kurdish People's Protection Units (YPG), the main Kurdish militia in Syria.

The US began supplying weapons directly to the YPG earlier this year as part of its support for the anti-jihadist Syrian Democratic Forces (SDF) alliance, which is dominated by the Kurdish militia.

The decision deeply angered Ankara, which considers the YPG a "terrorist" group.

Foreign Minister Mevlut Cavusoglu said on Friday that US President Donald Trump had told Turkey the weapons deliveries would end.

"Mr Trump said he gave a clear order and that after this, weapons would not be supplied to the YPG, essentially he said this nonsense should have been ended earlier," Cavusoglu said at a press conference in Ankara.

Washington was less explicit, describing only "pending adjustments" to its support for the YPG, which forms the backbone of the SDF that ousted the Islamic State group from Raqa last month.

"We are taking a hard look at the adjustments that need to be made to the military support provided to our Kurdish partners," Pentagon spokesman Colonel Rob Manning told reporters.

"We are always taking a look and assessing how we can do that better."

He said the US had always been clear that weapons provided to the YPG would be limited, "mission-specific", and provided incrementally.

"We are taking a look at the things that need to happen to make sure we are providing support consistent with those previous agreements," Manning added.

- 'No changes' in relations -

Kurdish officials told AFP on Monday that any changes to weapons deliveries were the natural consequence of their successes against IS, and not a reflection of any change in their ties with Washington.

"There are no changes to the relations between the Syrian Democratic Forces and the US administration," said Abdel Karim Amr, an official with the Kurdish semi-autonomous administration in northern Syria.

"Obviously, there will be an adjustment in the delivery of arms to the SDF after the elimination of IS, but there is no change in US policy regarding coordination" with the alliance, he added.

"The support will continue until we eliminate all that remains of IS's presence in the entire region where there is coordination between the US administration and the SDF," said Amr, who is charged with external relations for the Kurdish administration.

He described Turkey's statements on the issue as "incorrect" and "imprecise".

"We are the partners of the international coalition that is fighting terrorism, and that partnership will continue," added Mustefa Bali of the SDF's press office.

"We still have much to do with our partners in the coalition," he added.

The SDF has been a key partner of the US-led coalition against IS, and together they have driven the jihadists from strongholds including their one-time de facto Syrian capital Raqa.

But the relationship has caused tensions between Washington and Ankara, which launched its own military intervention in Syria last year targeting both IS and the YPG.

More than 340,000 people have been killed in Syria since the conflict began with anti-government protests in March 2011.