No decision yet on no-fly zone in Syria: US

Obama administration officials on Wednesday said the longstanding issue of a no-fly zone in war-torn Syria has been discussed but no decision made.

Washington's NATO ally Turkey, which has more than 1.8 million Syrian refugees on its soil, has argued for months in favour of a no-fly "safe zone" in northern Syria, where refugees could take shelter from the country's bloody civil conflict.

Spokesmen for the State Department and the White House fielded reporters' questions about a CNN report Tuesday that said Secretary John Kerry had asked his staff "to further develop the idea". 

CNN said Kerry also raised the issue at a National Security Council meeting last week.

The possibility of a no-fly zone in Syria - where a US-led coalition is striking at positions held by the Islamic State group - has come up occasionally since 2012, but never has been embraced by the administration of President Barack Obama.

State Department spokesman John Kirby declined to directly answer questions that any such recommendation had been made by his boss to the president.

Kirby did acknowledge, however, that the issue has been discussed.

"We continue to have discussions about how to best go after ISIL (Islamic State group) and particularly there in Syria, in northern Syria in particular," he said.

"And we've talked about the concerns that the Turks have expressed about the movement of ISIL there in northern Syria. 

"To date, there's been no decision to move forward with a no-fly zone."

His counterpart at the White House, Josh Earnest, was even more cautious when discussing the administration's position on a no-fly zone.

"We've not been in a position to take it 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.

"Even things that sound simple, like a no-fly zone, have significant consequences for longer-term strategic decisions that have to be made there."