An F-7 fighter jet of the Iranian Air Force crashed near the central city of Esfahan on Tuesday, killing both of the aircraft’s pilots.

The fighter jet crashed Tuesday morning at the Anarak training site located at the edge of Iran’s central desert of Dasht-e Kavir, some 200 kilometers east of the city of Esfahan.

Esfahan province's deputy governor Mohammad-Reza Jannessari said the aircraft was on a training mission.

The two killed pilots were identified as Lieutenant Colonel Qasem Zamani and First Lieutenant Mohammad Javad Baay from Esfahan’s tactical air base.

The Army’s public relations manager in the region, Colonel Mohammadi, told ISNA that the accident happened due to a technical problem, adding that further investigations are also underway.

Iran’s F-7 fighters are believed to have been modeled after China’s jet Chengdu J-7, whose third-generation export version is called F-7 and is considered a copy of the Soviet-era MiG-21. Beijing built the aircraft for export to countries including Pakistan, Iran, Sudan and North Korea. Iran has long been using the aircraft for training.

Iran’s air force has an assortment of Russian and US-made military aircraft purchased before the 1979 Islamic Revolution which are not considered to be in optimal condition as decades of Western sanctions have made it hard to maintain the aging fleet.

In February, an Iranian F-5 fighter jet crashed into a soccer stadium in the northwest city of Tabriz, killing a civilian and its two pilots.

Four years ago, another F-7 similarly crashed near Esfahan during an aerial exercise due to what was later described as a technical problem.