Kurdish fighters from the People’s Protection Units run across a street in Raqqa, Syria.

:: Turkey’s foreign minister assailed the United States on Monday, claiming that American forces in Syria are intentionally stalling the fight against ISIS militants as an excuse not to cut ties with Syrian Kurdish militiamen as Ankara has demanded.

Mevlut Cavusoglu told reporters in Istanbul that US forces are leaving “pockets” with ISIS militants intact to justify continued cooperation with the Kurdish militia.

Speaking ahead of a visit by US Secretary of State Rex Tillerson later this week, Cavusoglu said Turkey’s ties with the US are at a make-or-break stage and that Washington needs to take “concrete steps” to regain Turkey’s trust.

“Our relations are at a very critical stage,” Cavusoglu said. “Either we will improve ties or these ties will totally break down.”

Ankara is riled over Washington’s support for the Syrian Kurdish People’s Protection Units, or YPG – the top US ally in the fight against the Islamic State group.

Turkey considers the YPG a “terrorist” group linked to Kurdish insurgents fighting within Turkey’s own borders.

Turkey’s military launched a cross-border operation into the Syrian Kurdish-held enclave of Afrin in northern Syria to rout the YPG from the region.

Ankara has also threatened to expand its offensive to the YPG-held town of Manbij, east of Afrin, where the US has a military presence, setting the scene for a potential showdown between the two NATO allies that back different sides in Syria’s complex and multi-layered civil war.