A senior State Department official last Wednesday said that Turkey and the U.S. are not "having a conversation" on a no-fly zone in Syria, in a special briefing to journalists before Secretary of State John Kerry's trip to London.The official underlined the successful cooperation with Turkey across a number of areas, including the İncirlik air base in Adana, which the U.S. military wishes to use for its anti-ISIS air campaign in Syria. "The issue of armed platforms and things like that is a pretty intense conversation in the military-to-military channel and also diplomatic channels. It's just kind of a work in progress."Senior diplomats also claimed that there are de facto no-fly zones in certain areas given the density of coalition forces flights. "So to the extent there's any sort of a precondition for progress in certain areas based upon our doing a no-fly zone, that's not a particularly constructive conversation."News reports challenge senior officials' account related to de facto no-fly zones. Syrian President Bashar Assad's forces have been using the air force extensively, especially in Aleppo. Regime aircraft targeted Islamic State of Iraq and al-Sham (ISIS) strongholds on Tuesday and killed at least 43 civilians, wounding an additional 150 despite the heavy presence of coalition air forces, Reuters reported.Obama administration officials, speaking to the Washington Post on condition of anonymity last weekend, said that negotiations with Turkey regarding a possible exclusion zone along the Turkish border stalled over disagreement on priorities. An official said that the U.S. wants to go after ISIS, but Turkey is focused on Aleppo and Assad. U.S. media outlets previously reported that Turkey agreed to open the İncirlik base for the use of U.S. air forces and for sending its special forces to provide intelligence on ISIS targets in return for an exclusion zone in the north of Syria. Turkey also wanted to use this zone to enforce the Syrian opposition and to create a safe area for increasing numbers of refugees, as Turkey is already sheltering more than 1.5 million.Recently, Ankara's concerns regarding U.S. willingness to confront Assad increased following reports saying that Washington was more worried about a possible takeover of regime-controlled areas or more chaos in the south of the country in case of Assad's exit. President Obama also did not mention Assad in his State of Union speech, focused on his administration's efforts to counter ISIS's advance in Syria and Iraq."We're also supporting a moderate opposition in Syria that can help us in this effort, and assisting people everywhere who stand up to the bankrupt ideology of violent extremism," he added.