Istanbul: Iran says one of its fighter jets has gone down in the south of the country near the Persian Gulf, with two pilots surviving the crash.

The state-run IRNA news agency quoted a local official as saying the crash was caused by a technical problem. Abdolhossein Rafipour, the governor of Tangestan, says the plane went down near the coastal town at 12.30pm local time (1am AEST).

The purpose of Sunday's flight was not immediately clear. Regular patrol flights are common in the region.

Technicians work on Kowsar domestically-built fighter jet production line at an undisclosed location, Iran. Credit:AP

Iran's air force has an assortment of US-made military aircraft purchased before the 1979 Islamic Revolution. It also has Russian-made MiG and Sukhoi planes. Decades of Western sanctions have made it hard to maintain the ageing fleet.