White House spokesman Josh Earnest told reporters the US was "open to discussing a range of options with the Turks" but that a no-fly zone over Syria was not on the table "at this point."
Turkey has been pushing for a buffer zone inside Syria to shelter refugees from the three-way fight between Syrian President Bashar al-Assad's regime, rebels and Islamic State jihadists.
But Ankara, which has seen fighting on its southern frontier, has so far failed to persuade its NATO ally Washington, despite US jets already hitting IS targets inside Syria, to put its might behind the plan.
Since the civil war erupted in Syria in early 2011 there have been repeated calls for a no-fly zone to protect the rebels and refugees.
Former top US diplomat Hillary Clinton was apparently in favor of creating such a zone, but President Barack Obama has consistently ruled it out, concerned that Washington would be drawn deeper into the conflict.
This weekend US media reports suggested Washington's stance is shifting after a visit to Turkey last month by Vice President Joe Biden, but Earnest insisted this was not the case.
"We’ve made pretty clear on a number of occasions that while we’re open to discussing a range of options with the Turks... we do not believe that a specific no-fly zone proposal at this point would best serve the interests that we’ve all identified in terms of trying to resolve the situation in Syria," Earnest said.
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The Wall Street Journal reported that as part of a proposed deal between the US and Turkey, a protected "safe zone" along the border would be set up that would be off-limits to Assad's aircraft.
Narrower than a formal no-fly zone, it would not need any air-strikes. Instead the US would quietly warn the Assad regime to stay away, the Journal said.
In exchange US and coalition aircraft would use Turkey's Incirlik base as well as others to patrol the zone to make sure that rebels operating on the Turkey-Syria border do not come under attack.
The reports came just as Secretary of State John Kerry was heading to Brussels for talks on Wednesday with ministers from the 60-strong global coalition fighting the Islamic State group.
He will be accompanied by General John Allen, the US pointman forging the coalition to counter the threat from the group, also known as ISIL, which has captured a swathe of territory in Iraq and Syria.
"It's an opportunity to take stock of where things stand, obviously discuss what needs to happen from here, provide updates on where countries stand," said State Department spokeswoman Jen Psaki.
She said Washington continued to review a number of options including a no-fly zone, but insisted such discussions were "ongoing."
"We continue to have differences" with Turkey, Psaki told reporters, stressing "we haven’t made a decision about a specific course of implementation, we're just continuing to have a discussion with Turkey."