The United States is in talks with Turkey about the future support the U.S. military will provide Turkish forces around al-Bab, Syria, a U.S. military spokesman said on Wednesday, adding that he expected the assistance to continue.

"There have been discussions at the diplomatic level about the way ahead," Air Force Colonel John Dorrian, a spokesman for the coalition fighting Daesh, told Pentagon reporters.

"We do expect that there will be some ongoing support to Turkish operations in and around al-Bab," Dorrian said, confirming that U.S. warplanes had supported Turkish forces near the town last week. He declined to say what U.S. support was available but said Turkish officials knew what was on offer.