The United States has not made a decision over whether to deploy Patriot batteries to Turkey’s southern border after receiving a request from Ankara, a US official told Al-Monitor. The ask comes amid ongoing clashes in Syria’s opposition-held Idlib province as two Turkish troops were killed in a regime airstrike on Thursday.

Bloomberg first reported that Turkey had requested two missile batteries through US Special Representative for Syria Jim Jeffrey, who served as the US envoy to Ankara during the George W. Bush and Barack Obama administrations. It was not immediately made clear to Al-Monitor when the request came through, how it was conveyed, how many batteries Turkey asked for or whether Ankara asked to purchase or borrow the units.

Any Turkish deal for Patriot batteries could face challenges, as the Donald Trump administration already nixed a $3.5 billion deal for the US-made missile defenses after Ankara took delivery of the Russian S-400 air defense system in July. The Pentagon had long feared that the powerful radar system onboard the Russian weapon could be used to erode the capabilities of the F-35 fighter jet.

Turkish media reported on Friday that the United States had turned down the request. But the United States would likely not be in a position to approve or deny such a request made through Jeffrey since Turkey would be required to notify the Defense Department of their formal interest in the Patriot system through a letter to the agency. The Pentagon would then have about four months to respond.