TEHRAN, Iran — Iran's state media say the country's navy has taken charge of four new Iranian-built submarines as part of Tehran's efforts to upgrade its defense capabilities.

The official IRNA news agency says Defense Minister Gen. Ahmad Vahidi and Navy chief Adm. Habibollah Sayyari attended Sunday's ceremony marking the delivery of the vessels to the Iranian navy.

IRNA says the Ghadir class submarines can fire missiles and torpedoes at the same time and can operate in the Persian Gulf's shallow waters.

Iran has sought to upgrade its air defense systems and naval power, saying any possible future attacks against Iran will be air and sea-based.

Iran has also three Russian-made submarines.