TEHRAN, Iran — Iran has banned its airlines from leasing more Russian-made aircraft or buying such planes secondhand after two fatal incidents last month, a senior transport official said in remarks published Tuesday.

On July 15, a Russian-built Tupolev operated by Iran’s Caspian Airlines flying to Armenia crashed in northwestern Iran, killing all 168 people aboard.

Nine days later, 17 people were killed when an Ilyushin Il-62, also made in Russia and leased by Iran’s Aria Tour from Kazakhstan, veered off the runway and hit a wall in northeastern Iran.

“Based on the new directive which went into effect on Sunday, no [entity] would be permitted to enter leased or used Russian planes into the country’s air fleet,” said Mohammad Ali Ilkhani, who heads Iran’s Civil Aviation Organization.

Expressing a preference for Western-made aircraft, he was also quoted as saying by the Resalat daily, “Eastern planes would be able to operate in the air sector only when they are brand new and made according to our order [specification].”

Ilkhani, who did not mention the Russian-built planes already in service in Iran, is also the deputy road and transport minister.

U.S. sanctions bar the sale of Boeing aircraft to Iran and hinder it from buying other aircraft or spare parts from the West. Many Western aircraft rely on U.S.-made engines and parts.

Air safety experts have said Iran has a poor record, with a string of crashes in the past few decades — many involving Russian-made aircraft.