© Fatih Saribas / Reuters
The authorities entered the base in southern Turkey on Monday, state-run Anadolu news agency reported, adding that the investigation is connected with the coup attempt.
Over the weekend, the airbase's commander, General Bekir Ercan Van was detained at Incirlik by Turkish authorities along with over a dozen lower ranking officers. They all stand accused of complicity in the attempted coup.
Authorities have also reportedly claimed that at least one of the F-16 fighter jets "hijacked" by the coup plotters was refueled by an aircraft that had taken off from the Incirlik base.
The air base, which is used by NATO and stores US tactical nuclear weapons, has been recently used by Washington in its campaign against Islamic State (IS, formerly ISIS/ISIL) in neighboring Syria.
The airbase was blocked by Turkish military authorities following the failed coup attempt, leading to the cancellation of airstrikes on IS targets.
The electric power supply to the base has also been cut off, forcing the US military to switch to its own internal power supply in order to resume its anti-terrorist campaign in the region.
Comment: The Incirlik airbase is an important aspect to both the failed coup as well as the messages being sent regarding the base. The US and its NATO forces certainly do not want to lose one of their primary footholds for organizing terror in Syria and Iraq. Turkey knows it was the US who was behind the coup, and it is clear that Turkey is taking measures to weed out the Western influenced 5th column. Of course, Washington is spinning this as Turkey spinning out of control and over-reaching after the coup. Given Erdogan's unstable personality, he may provide fuel for the fire.