Twelve US F-15 fighter jets deployed temporarily in Turkey’s Incirlik air base last month returned to their Lakenheath airbase in the UK on Wednesday, one day after US Defense Secretary visited the location.

Twelve US F-15 fighter jets deployed temporarily in Turkey’s Incirlik air base last month returned to their Lakenheath airbase in the UK on Wednesday, one day after US Defense Secretary visited the location.

The US European Command (EUCOM) said that the temporary deployment strengthened interoperability of the US and Turkish air forces in defending Turkish airspace and conducting alleged operations against the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group.

"During this deployment, a bilateral agreement was finalized that outlined the procedures for combat air patrol missions to be flown by US pilots and aircraft," EUCOM said.

The US had deployed six F-15C warplanes to Incirlik on Nov. 6 on the request of Ankara, in order to strengthen Turkey’s air defense against possible threats from Syria.

"This deployment served not only as an immediate response to a request from an ally, but as an exercise for the US Air Force ability to deploy aircraft and airmen on short notice to Turkey, if ever needed," EUCOM said.

Six other F-15E type fighter jets were deployed in Incirlik on Nov. 12 to conduct operations against ISIL in Syria and Iraq.

The US European Command stressed that the end of F-15 deployments does not indicate a reduction in operations against ISIL group.

"Coalition aircraft operating from Incirlik are expected to increase and continue to increase in the coming months," EUCOM said.