Iran has reached a deal to buy 100 planes from U.S. planemaker Boeing, and the two sides are awaiting approval by U.S. Treasury authorities, the head of Iran's Civil Aviation Organisation said in remarks published by state media on Sunday.So far, Boeing has only been granted permission to presentits products to Iranair and a handful of other airlines as ittries to catch up with Europe's Airbus, which won aprovisional deal earlier this year for 118 jets worth $27billion.Reuters reported on June 6 that Iran was edging towards ahistoric agreement to buy jetliners from Boeing for the firsttime since the 1979 Revolution and that a deal for morethan 100 aircraft could be reached fairly soon."Of the 250 (passenger) planes in Iran, 230 have to bereplaced," Ali Abedzadeh, the head of Iran's Civil AviationOrganisation, told the state-run daily newspaper Iran, addingthat a written agreement had been signed with Boeing to buy 100aircraft.Abedzadeh said that no precise timeline could be given forthe implementation of the deal before an authorisation is issuedby the U.S. Treasury Department."The final obstacle in this area are only the permits fromthe U.S. Treasury Department," Abedzadeh told the Irannewspaper.In January, Iranair agreed in to buy 118 jets worth $27billion at list prices from Airbus. The deal was conditional onU.S. export licenses because of the quantity of U.S.-built parts.