Top diplomats from the U.S. and Britain said Wednesday they would consider supporting a buffer zone inside Syria to help protect Turkey's borders, but a Pentagon spokesman said that is not an option that is currently on the table.

Still, asked about a buffer zone after an hour-long meeting in Washington, Secretary of State John Kerry British and visiting British Foreign Minister Philip Hammond both stopped short of embracing one. The issue comes as the U.S. is prodding Ankara to ramp up action against the Islamic State militant group, which is closing in on the Syrian town of Kobani that sits on Turkey's border.

Turkey has long called for the creation of a buffer zone inside Syria as well as a no-fly zone to secure Turkey's borders and stem the flow of refugees. But the Pentagon has maintained that doing so would be costly and controversial, largely because it would need to be accompanied by a no-fly zone overhead.

Both Kerry and Hammond told reporters that the concept of a buffer zone would need to be carefully examined, including with other nations, to see how it would work.

"But I certainly wouldn't want to rule it out at this stage," Hammond said.

Kerry said the issue would be raised later this week at a meeting of U.S. officials and Turkish leaders. "It's worth examining. It's worth looking at very, very closely," Kerry said.

The siege on Kobani remains a top concern for both the U.S. and Turkey, Kerry said, noting that American airstrikes have targeted militants nearing the border town.