"We've not been in a position to take it [the possibility of a no-fly zone in Syria] off the table or to rule it out in the future, but we have indicated that it's not something that we're considering right now," Earnest told reporters on Wednesday.
At a separate briefing, State Department spokesman John Kirby did acknowledge, however, that the issue has been discussed.
"We continue to have discussions about how to best go after the Islamic State group and particularly there in Syria, in northern Syria in particular," he said. "To date, there's been no decision to move forward with a no-fly zone."
John Kirby however declined to directly answer questions about the reports that US Secretary of State John Kerry has asked his staff "to further develop the idea."
However the position of President Obama on the issue is somewhat different.
"When I hear people offering up half-baked ideas as if they are solutions, or trying to downplay the challenges involved in this situation — what I’d like to see people ask is, specifically, precisely, what exactly would you do, and how would you fund it, and how would you sustain it? And typically, what you get is a bunch of mumbo jumbo," the president said last week.