* ATR says has delivered 13 of 20 aircraft ordered by IranAir
* Planemaker, governments have been lobbying U.S. Treasury
* Says now seeking authorisations for maintenance (Recasts with ATR statement, adds bullet points)
DUBAI/PARIS, Aug 5 (Reuters) - ATR on Monday confirmed it had delivered five more turboprop aircraft to IranAir shortly before Washington imposes new sanctions on Iran but said it still faced difficulties obtaining U.S. permission to hand over another seven planes on order.
Washington is poised to hit Tehran with the economic sanctions after President Donald Trump in May exited a nuclear pact between Tehran and major world powers.
His decision requires most companies to complete ongoing business with Iran before U.S. sanctions are reimposed after a wind-down period which expires on Aug. 6.
ATR has now delivered 13 of the aircraft sought by IranAir and another seven remain on order.
"The next step will consist in working on getting an appropriate authorisation from the U.S. administration to ensure a reasonable level of maintenance," ATR said in a statement.
"We still have challenges to face with the remaining aircraft originally intended for Iran," the planemaker added. "We will dedicate the remaining part of the year to execute our plans as foreseen."
All five new ATR 72-600 planes landed in Tehran's Mehrabad airport after leaving Toulouse, France, where they were built, and refuelling in Urmia in northwestern Iran, the Iranian news agency IRNA reported.
ATR - co-owned by Airbus and Italy's Leonardo - has been pressing U.S. authorities to allow it to deliver aircraft it built for Iran.
After the signing of the accord in 2015 to reopen trade links in return for Tehran curbing its nuclear activities, IranAir ordered a total of 200 aircraft from Western planemakers including 20 from ATR, which is based in Toulouse.
Few, however, have been delivered and planemakers say they are unable to use the wind-down period because Washington has also revoked export licences needed by all Western planemakers due to their heavy use of U.S. parts.
ATR lobbied the U.S. Treasury to allow it to take advantage of the normal wind-down period for Iran business by giving it temporary new licences.
Asghar Fakhrieh-Kashan, an adviser to Iran’s transport minister, was quoted by the semi-official news agency ILNA as saying that Iran had paid for the five planes on Friday, a day before the planes left France.
"The delivery of these five aircraft is a sign of Europe's commitment to the nuclear accord," Fakhrieh-Kashan told ILNA.
The U.S. decision on Iran has raised question marks over whether ATR can reach a target of stabilising annual deliveries at 80 aircraft in 2018.
The planemaker has said it will suffer financial damage if it cannot deliver the aircraft it has already produced following earlier U.S. approvals, and is looking for alternative buyers.
Airbus said last month it would not attempt to deliver any more planes to Iran in the wind-down period. It has delivered just three of 100 ordered by IranAir.
Boeing, which had sold 80 jets to IranAir under the 2015 nuclear deal, does not plan any deliveries. Unlike the European firms, it never placed the Iranian deal in its official order book on the grounds that it never received a deposit. (Reporting by Dubai newsroom and Richard Lough in Paris Editing by Raissa Kasolowsky and Adrian Croft)