Two acting chief prosecutors, accompanied by police, have started searching a key air base in southern Turkey used by the United States for air raids on the Islamic State group, the state-run Anadolu news agency reported Monday.
Authorities had earlier detained a senior air force general and a dozen other suspects accused of backing the failed coup at the Incirlik air base in the Adana province close to Syria, officials said at the weekend.
Officials have said the authorities suspect that Incirlik was used by rogue troops to refuel military aircraft "hijacked" by the coup plotters on Friday night.
The report did not specify what evidence the investigation team was seeking.
The base has become a key hub for US forces after Turkey last year agreed to allow the United States to use Incirlik to carry out lethal raids against jihadists in Syria.
Washington said Sunday that strikes had resumed from the base, after Turkish authorities imposed a security lockdown on the base and closed airspace in the surrounding area.