The U.S. has established a new military base in Syria's northern city of Hasakah, Irbil-based Kurdish Basnews reported on Sunday.Speaking to Basnews, a source from the Syrian Democratic Forces (SDF) reported that the U.S. has stationed 800 commandos at the base, which is located to the northeast of the city of Hasakah.Most of the districts in Hasakah have been under control of the Syrian offshoot of the PKK terrorist organization, the Democratic Union Party (PYD) since 2013.The move is perhaps one of the most emboldened by the U.S. since tensions arose between Ankara and Washington due to the U.S.'s controversial support for the SDF, which is predominantly led by the PYD.Although the Obama administration has long argued that the SDF is the most effective "partner" of the U.S.-led coalition against Daesh, Turkey considers the PYD a terrorist organization due to its organic links with the PKK. In this regard, Turkey has declared numerous times that one terrorist group cannot be used to eliminate another terrorist group.Moreover, the U.S's reluctant attitude to provide support to NATO-ally Turkey and Turkish military forces on the ground in al-Bab have drawn strong reactions from Ankara.The U.S. has three additional military bases which are located in PYD-controlled areas.Turkey considers the PYD and its armed wing, the People's Protection Units (YPG) to be a terror threat, saying that these organizations are an offshoot of the PKK, which is officially recognized as a terrorist organization by the U.S., the E.U. and Turkey.However, the EU and the U.S. do not recognize the PYD-YPG as a terrorist organization. Turkey strongly opposes the presence of any PKK-affiliated group south of its border, both in Iraq and Syria, saying it constitutes a national security threat to Turkey's borders.YPG terrorist Paolo Todd, who is a U.S. citizen, was killed during clashes with Daesh on Jan. 15, several Kurdish news outlets reported Monday. Todd, who was known by the code name "Kawa Ahmed" among YPG terrorists, had reportedly joined the YPG on November 4,2016 while living in Los Angeles.