(AFP) - Iranian carriers Iran Airtour and Zagros Airlines have agreed to buy a combined 73 planes from Airbus, the European aircraft maker said on Thursday at the Paris Air Show.

Following the end of international sanctions over Tehran's nuclear programme, Iranian airlines are back in the market, seeking to upgrade their ageing fleets and expand their networks.

Iran Airtour Airlines, which runs domestic and regional scheduled services, signed a memorandum of understanding to purchase 45 aircraft of the single-aisle A320neo family, Airbus said in a statement.

Airbus said separately that Zagros, which flies domestic routes in Iran, had signed a memorandum of understanding to pick up 20 planes of the A320neo family, and eight of the A330neo type.

Zagros is already the largest operator of Airbus single-aisle aircraft in Iran with 11 A320ceo planes, it said.

Like Airtour, Zagros will use the new planes to upgrade its fleet and expand operations both at home and internationally, Zagros CEO Seyed Abdolreza Mousavi was quoted in the statement as saying.

Both deals still need a number of authorisations before being confirmed, notably from the Office of Foreign Assets Control (OFAC), a US Treasury Department body that administers and enforces American sanctions against foreign countries.

Several international sanctions against Iran were lifted following a nuclear deal with Tehran in July 2015, including those banning the sale of commercial aircraft to Iran.

According to estimates from the Iranian civil aviation authority, the country's airlines will need to purchase between 400 and 500 new planes over the next decade.