The drills involve submarines and drones "practicing information-gathering operations against attacking forces, as well as reconnaissance operations,” Admiral Habibollah Sayyari told the official IRNA news agency.

The exercises, code named Zolfaghar-1401, were launched overnight Friday in the eastern side of the strait in the Gulf of Oman.

Tehran, which opposes the presence of US and Western navies in the area, holds annual war games in the Strait of Hormuz, the conduit for some 30% of all crude oil traded by sea.

Sayyari said foreign forces must leave the area "so that regional countries can establish stability and peace in their neighborhood," the English-language state-run Press TV reported.