A passenger plane carrying around 60 people has crashed in a mountainous area of central Iran, media report.

The plane came down in the Zagros mountains near the city of Semirom in Isfahan province while flying between Tehran and the south-western city of Yasuj, reports say.

"All emergency forces are on alert," an emergency services spokesman said. "The plane had 50 to 60 passengers."

Bad weather reportedly prevented an emergency helicopter reaching the site.

There is no word yet on casualties.

The plane, believed to be an ATR 72-500, was operated by Aseman Airlines.