Tehran: Iran and US aerospace giant Boeing have reached an agreement for the purchase of 100 aircraft to renew the country's ageing fleet, the head of Tehran's civil aviation authority announced on Sunday.

"We have 250 planes in the country, 230 need to be replaced," said Ali Abedzadeh, the head of the civil aviation body, adding that the deal still needed approval from the US government.

In an interview with the Iran daily newspaper, Abedzadeh said there could be no precise timeline for the contract without US Treasury permission.

Iran has ordered about 200 planes from three Western manufacturers since mid-January when economic sanctions were lifted following a deal on Tehran's nuclear programme.

Boeing confirmed on Wednesday that it was in talks with Iranian airlines interested in buying its passenger planes.

"We have been engaged in discussions with Iranian airlines approved by the (US government) about potential purchases of Boeing commercial passenger airplaned and services," the company said in an email to AFP.

Many of Iran's ageing civil aviation fleet are in desperate need of replacement.

In February, the American company was granted approval from the US government to explore resuming sales to Iran after US sanctions were partially lifted in January.

Boeing has requested final authorisation from the US Treasury for the sale of aircraft, Abedzadeh continued.

He said the reported value of $17 billion (15 billion euros) for the contract was not final and that more details will be provided after further negotiations.

Iran in January reached a memorandum of understanding with European aircraft manufacturer Airbus for the purchase of 118 planes.

That agreement is still pending permission from the US Treasury.

Airbus needs the approval of the US Office of Foreign Assets Control because more than 10 per cent of Airbus components are of American origin.