ANKARA — Turkey has completed upgrades on two Ay-class submarines, contractor STM said Thursday.

STM, an Ankara-based defense technologies company, said that it finished the upgrades which it had started four-and-a-half years ago. The upgraded Turkish submarines are the TCG Dognap and TCG Tolunay.

STM said this is the first time a Turkish non-military company has completed a program as prime contractor.

The upgrade program involved modernization of electronic support units, attack systems, cruise systems and cruise periscopes.

The upgrades were done at the Turkish Navy's Golcuk Shipyards Command southwest of Istanbul on the Marmara Sea coast.

STM said it also will provide local content to Turkey's national submarine production program.