Turkish President Recep Tayyip Erdogan condemned on Tuesday the United States’ decision to continue on financing the Syrian Kurdish People’s Protection Units (YPG). He said that the move will affect Turkeys decisions. He made his remarks ahead of a two-day visit by US Secretary of State Rex Tillerson to Turkey, which he kicks off on Thursday. US officials have said that Tillerson expects to have difficult conversations when he visits the country, given that the NATO allies have starkly diverging interests in Syria. Turkey has been enraged by US support for the YPG, which Ankara sees as a terrorist organization and an extension of the outlawed Kurdistan Workers Party (PKK). Washington has backed the YPG in the fight against ISIS in Syria. “Our ally’s decision to give financial support to the YPG... will surely affect the decisions we will take,” Erdogan said in a speech to members of his ruling AK Party in parliament. His comments followed the release of the US Department of Defenses 2019 budget, which includes funds to train and equip local forces in the fight against ISIS in Syria. Turkey last month launched an incursion into Syria, which it calls “Operation Olive Branch” to sweep the YPG from its southern border. It has also threatened to press on to the Syrian town of Manbij, under the control of a YPG-led force, and has warned American troops stationed there not to get in the way. Washington says it has no plans to withdraw its soldiers from Manbij and two US commanders visited the town last week to reinforce that message. “It is very clear that those who say ‘we will respond aggressively if you hit us’ have never experienced an Ottoman slap,” Erdogan said in parliament. That was an apparent reference to comments made by US Lieutenant General Paul Funk during a visit to Manbij. On Monday, Turkish Foreign Minister Mevlut Cavusoglu accused American forces in Syria of intentionally stalling the fight against ISIS as an excuse not to cut ties with the YPG. He told reporters in Istanbul that US forces are leaving "pockets" with ISIS terrorists intact to justify continued cooperation with the YPG. He added that Ankara’s Turkeys ties with Washington are at a make-or-break stage and that it needs to take "concrete steps" to regain Turkeys trust. "Our relations are at a very critical stage," Cavusoglu said. "Either we will improve ties or these ties will totally break down."