A U.S. Air Force F-16 Fighting Falcon from Aviano Air Base, Italy, is seen at Incirlik Air Base, Turkey, after being deployed, in this U.S. Air Force handout picture taken August 9, 2015. REUTERS/U.S. Air Force/Senior Airman Michael Battles/Handout

WASHINGTON (Reuters) - The U.S.-led coalition carried out flights in support of Turkish forces near the Islamic State-controlled Syrian town of al-Bab last week but did not carry out air strikes, Pentagon spokesman Peter Cook said on Tuesday.

The flights were meant as a “visible show of force,” Cook said,

“My understanding is that last week there was a request when some Turkish forces came under fire for air support and there... were flights conducted by the coalition at that time,” Cook said.

The U.S.-led coalition has been reluctant to provide support to NATO member Turkey for its advance towards al-Bab. Turkey recently called on the coalition to provide air support for Turkish-backed troops besieging the town.

Rebels supported by Turkish troops have laid siege to al-Bab for weeks under the “Euphrates Shield” operation launched by Turkey nearly four months ago to sweep the Sunni Muslim hardliners and Kurdish fighters from its Syrian border.

A U.S. defense official, speaking on the condition of anonymity, said the flights took place on Thursday.