“General John Allen will hold talks in Ankara today,” a Turkish official told AFP on condition of anonymity, adding that the talks were “naturally” expected to focus on the fight against IS.

Accompanied by U.S. Undersecretary of Defence for Policy Christine Wormuth and military officials, Allen is expected to meet with Feridun Sinirlioglu, the Turkish undersecretary of the foreign ministry as well as military chiefs, the source said.

Turkey has reinforced its military presence on the volatile border over the past week, deploying tanks and anti-aircraft missiles there as well as additional troops.

The moves come as fighting between Islamist-led groups and Syrian regime forces in the northern city of Aleppo has intensified.

The Turkish build-up has led to speculation that the government is planning to intervene in Syria to push the militants back from the border and halt the advance of Kurdish forces who have made gains against the extremists in the area.

Reports last week said the Turkish military could create a buffer zone dozens of kilometres inside Syrian territory to ensure Turkish security and house some of the 1.8 million Syrian refugees on its territory.